Love cats, but am allergic now, just have kids, but check out this article. Also many cool products for cats:
https://www.houzz.com/magazine/houzz-tour-for-the-love-of-a-cat-in-philadelphia-stsetivw-vs~4185342

Will you have any yard at all? Were the cats raised indoors or were they rescue cats?

It will be hard for them ... And for you. Can you not train them to adapt to the new area? Basically go out with them for a few minutes each day, gradually increasing the time. There are probably online training programmes

oh oh :) I don't think they will be too happy staying indoors all the time after having known the outdoors..judging by those photos..we used to have three cats and even when they were geriatric they still wanted to be outdoors.
they had perches by every available window which they need to guard their domain :) you might want to consider leashes to take them out for walks or to put them out for a little while?

You can get a cat run for the yard where you're moving to. I worried about my indoor/outdoor cat too, we had a three month stint in an apartment between selling and buying, but he did fine. I bought a LOT of toys and some catnip mice and we played with him a lot. We did have a screened in porch and let him go out there, but we didn't let him outside once the entire three months and we all lived through it. ;o)

Try a Google search for enclosed cat spaces to see some ideas. http://www.nytimes.com/2010/06/17/garden/17catio.html?pagewanted=all&_r=0

I was in a situation similar to yours, but had no yard. I trained a ten-year-old cat to wear a harness and tolerate a leash. It was not easy.

I agree with the above suggestions to put perches at every window.

Perhaps you could install ledges above doorways, carpeted climbing poles from floor to ledge, and so on.

Here are a few photos of rooms attached to houses that i think cats would enjoy. They are from Houzz. I am sorry they do not enlarge on this post.

@zwizzle1. Nice "catio" photos at the site you suggested!

http://pinterest.com/pin/210754457534486941/ is a cat tunnel attached to fences, leading to a shelter.

http://pinterest.com/pin/210754457534262587/ combined with http://pinterest.com/pin/210754457534675277/ could work for you.

Try typing "cat fence in system" into your browser's search engine. Cat Fancy magazine also carries ads in every issue with cat products.
This is the one I used 20 years ago (it was the only thing available at the time). It's far from perfect, but it does allow my cats to roam the backyard. We had to replace all of the netting a couple of years ago because of UV deterioration. If you have racoons at your new home, be prepared to have to repair the fence often. Don't leave any food outside at night -- then wildlife like racoons, skunks and rodents won't be inclined to tear through the fencing (which is actually "bird netting") to get into your yard.

website:
http://www.catfencein.com/

There may be better products out there now -- computers have made searching for specialty products SOOOO much easier! Expect your cats to protest the new arrangement for the first couple of weeks. And they're just like 2-year-olds -- they won't be impressed at all when you tell them "it's for your own good." =^. .^=

Here's a website I just found:
http://www.cat-lovers-only.com/cat-fence.html
P.S. You have gorgeous cats!

You're getting good advice. I'll just confirm all of the above, and lots of loving on them until they adjust. You're a good parent to be looking out for them in advance.

My husband built the most extraordinary outside cat space. (He says he doesn't like cats.) It is under our deck, and a story high. He installed a pet door in the basement window. Then he put wire fencing around a space, using the support columns to staple the fencing. He has a door in this area so that he can get in and out to spiff it up. He built her a sand box (with sand from Toys R Us….no bugs), dragged in a felled tree, and hung toys.

Don't you just love your babies?

This woman created an outside cat enclosure for her kitties that expanded around her yard. She also gives details on how she did it, so check this out: http://cuckoo4design.blogspot.com/2012/05/cuckoo-for-my-cats.html

I've had five all-indoor cats and some transitioned as rescue cats from bedraggled lives outside. They will likely have no problems at all. :) Mine can access a large outdoor side yard with walls too steep to climb but enjoy sitting outside on window ledges. They need things to do inside as well -- good viewing points to the outside, a few climbers/scratchers, toys. I know many cats who have gone over cat fencing and then cannot get back in, so not a big fan of that approach. There are loads of images around the net of cat enclosures, some pretty amazing. We'll be building one on my partner's house as I'll be moving over there soon, so I too have been searching out ideas.

This was incredibly helpful--thank you!!

Ooh- KB, can you send the photo of the wool cat bag over to jcorrigan's monster fireplace discussion?!

My mom built a walk out tunnel from a window in the house. The cats love it. But she didn't put the posts in concrete and a huge storm came and knocked it over. But the cats did get to enjoy it for a while.

I have worked with TNR, ferals, and house cats for several years now, and yes, you can keep them inside, and they will be fine. Giving them an enclosed outdoor space will make all of you feel better perhaps, and I am building one for my cats this summer, but they don't need it. They will love it though. They will perhaps make noise and bug you to let them out until they realize that "out" is no longer an option. You will have to be very very careful when coming and going as they may try to shoot out the door when it is opened. One of the problems there is you will be in a totally new area. Check this out for all sorts of ideas. Good luck, it will be fine. I have several cats that were outdoor cats and now are strictly indoors.
http://catioshowcase.com/

We are cat and dog people....we have many cats and are done in that department. 3 x ferals. They make wonderful pets.

search "catio" for some great enclosure ideas

Wow, those cats are lucky above!

from catioshowcase.com

I have worked with ferals and have converted a few of them from their totally outdoor life to living inside. First they will all need some time transistion just for the move. On average two weeks. A friendlier cat will adapt sooner, a timid cat (scardie cat - I like to call them :)) will take longer. At first create "caves" for them. They will want to hide. Keep their litter and food within easy reach - after they adapt you will be able to transition the litter box to a more convienient place.
My most "feral" feral - loves hiding under plants. Her favorite is a huge Aspargus Fern that sits on the floor and drapes over the pot. The plant is full enough that they don't attempt to use it as a litter box. Keep the litter box clean and they shouldn't bother the plants. Do some research on any plants you bring in to make sure thay are non-toxic.
Give them window access. They will love looking outdoors and laying in the sun.
Change their diet to indoor foods - they will need the extra fiber ( just like us!!!!). You may have to add a hairball releif medicine to some wet food. Especially a long hair cat or one that sheds alot. I use a gel that I buy at a pet store.
Speaking of shedding...ugh!...regular brushing will help...and your cats will love you for it.

Good luck with the transition.

Yes, and as mocreidhe suggested - be VERY careful of them "shooting" out of the door. I don't mean to scare you but a good chance they will run away. A pet crate may be a good idea during the actual move to keep them confined while doors are opened and closed for moving furniture.

I absolutely love all the ideas that have come from this post!! I never even thought of a cat "enclosure" before. We have 3 indoor cats, which have taken a liking to escaping the house and roaming the area. We are on 3 rural acres and the coyotes, hawks, and owls are natural predators. We used the electric fence when we had dogs, but won't go that route with the cats, since it keeps them close, but offers no protection from the predators . The neighbor cats have taken a liking to taunting and teasing our indoor cats through the window screens. Over half of all the screens that I replaced last spring are ruined from cat fights. Plus, mine learned how to open the patio screen doors! I put on locks. Then they ripped holes through the screens to escape. So yes, taking cats who are accustomed to being outdoors and making them strictly indoors may be a difficult task. All the nifty information that has been supplied above will surely give you some options. P.S, Your orange tabby looks like my Frankie.

awwww :-)

My once feral cats could care less about being outdoors. They only want to keep going outdoors if you keep going back and forth and don't make up your mind to make them strictly indoor cats. Because once a cat gets the security of being inside , they don't like how it feels to be outdoors....for example, when they first come inside, they don't like the feeling of having a roof over their head-literally and then they get used to luxuriating in shelter. Then when you try to get them to walk around the hallways or any area that is foreign to them, then they get all panicked and especially outside. The openness scares them.