How about having a sink made from soapstone, or fire clay, mounting it on a metal frame work? Or find a real porcelain, very large size bathroom sink. Alternatively how about one made of Silgranite (or its cheaper look-alike from Home Depot). I'm not sure how that material would stand up to strong, direct sunlight outdoors, however. Then there's always stainless steel, as long as there was no wooden subtrate involved. If you're thinking of SS, try looking for an old restaurant sink with an attached metal counter/drainboard. You could try out the plan using any old sink you find in a junkyard.

For plumbing in any area where there was even a chance of frost I'd use those "freeze-proof" hose bibs connected to hose-like flexible supply lines; connected, in turn, to the faucet assemblies. Plus inside the house I'd have line shut-offs, and possibly drains, for easy emptying and protecting the system. The hose-to-regular plumbing connections will have to be thought through as you will run into the annoying fact that there are the so-called hose threading and pipe threading, which while looking similar do not mate with each other. You may need a "from-scratch" type plumbing shop to customize your supply line arrangements.

For the drain you could either just let the water drain onto the ground, or do a large french drain type cachement area underfoot to absorb the water. Think about what cleaning products and soaps you might need when deciding whether to connect to existing waste disposal.

You may also have code issues about this set-up to deal with.
L

I use a garden cart with a hose attachment sink for dyeing and I wouldn't recommend it for the rigors of remodeling cooking. How about an inexpensive stainless steel sink? There are plenty in your price range, and you can temporarily mount on in plywood or hard backer or whatever on sawhorses, and do the whole shebang for your $300.

Or buy/build a proper potting bench that would be useful for your other tasks in the future, and provide you with a "kitchen" counter during reno. If this is going to be your food prep area and you can plumb it to your hot water you will be soooooo much happier.

Oh. Forgot the most important thing!! You need a lid. Trust me. Fitted is best, but even just a board to keep the big stuff out.

we just installed a SS sink from Lowes into granite on our deck. The deck needs to be refinished, so I guess we did it a little backwards (for a change) but so far it's working for us. Actually, real handy since we don't currently have a kitchen with a sink.

Thanks! And remodelfla, love yours (and your pool, too!) :) Do you have that connected to actual plumbing, or just a hose?

The funny part is that we actually have one of those big laundry sinks (except an old concrete version circa 1925---once upon a time the washer was in there) down in our basement, though the plumbing has been disconnected---getting it up and running is on our long-term list of things to do, but I was thinking it wouldn't be such a hot renovation sink since there's no access to the basement from the house, so you have to walk out and through the garage to get there. Maybe I should reconsider that, though, since it would be great to have it working. Sadly when they redid the foundation at some point, they poured it around the sink's legs (?!?) so we can't move it.

Stainless in plywood is a good thought too---we could just use the existing sink once demo's done, actually. Hadn't even thought about hot water...

my brother-in-law , who is a landscaper, installed a laundry-type sink near their shed as a permanent fixture for the gardening chores. Mind you they don't need to worry about freezing temperatures.
I always find it very useful. Wash the animals food dishes in there as well as all the gardening type stuff

just a thought

I know this sounds strange but if you google "Fish cleaning table with built in sink" you will come up with all sorts of ideas.

My daughter found our old porcelain sink in a friend's junk pile. I had planned to build a frame for it, but we found some salvaged lab tables, and used one of the left-over frames. It's not plumbed, but a spigot is just around the corner, and it drains over a graveled French drain.

Here is a link that might be useful:

He actually buried a hose from the side of the house under the deck and through PVC piping up to the sink.