Ok, thank you for the advice

sephia is correct. I understand your boyfriend's feelings as we also feel nervous about having people we don't know well come in (especially my husband). Will they remember to come, will they lock up properly, are they snoopy, are they responsible?

No one you know would be willing? I would say boarding is your best option, but the one time we boarded our cat, she refused to eat which was a problem. So we have someone come in to care for her.

Check to see if there is a Fetch Pet Care near you. They are a company which has "tried and true" experienced workers who will visit your home to spend time with your pets, clean litter box, feed the, check water, etc. You can just tell them this is your first time and you'd appreciate someone from their crew who is well known to them as a dependable person. He/she will come to your home so you can show what to do, give key, etc. I know it's an expense, but it's worth it to be sure your animals are safe. And once you get set up with them, you can feel free to take other trips and know you won't have to worry about the kitties.

If you don't have Fetch Pet Care, you may have another pet care company in your area. Remember to yelp them to see the reviews.

https://www.fetchpetcare.com/

Having someone come over would be best. Leaving them for a couple of nights would be ok; you could put out plenty of food, water and extra litter boxes. But 4 nights is a long time. You could board them. We boarded one of ours once because he needed meds nightly and my MIL advised that she might have to stop by in the mornings sometimes.

Long time cat staff here. With cats that got along, 2... maybe at the very most 3 nights was the absolute max time I felt I could leave them alone. Now I have cats with issues so 1 night is really about as far as I'll push it.

As others have mentioned, the litter box would become a nightmare and do you really want to risk someone developing a litter box aversion? Also - hey - these are domesticated animals who do depend on us for affection and companionship, even though your cat may try to deny it. Mine would always seem so discombobulated after even 2 days, let alone 3... like they were starting to revert to the wild.

If you are considering boarding, then why not hire a professional cat sitter to come in? Someone bonded and insured - not some kid from down the street who may or may not show up. Nowadays, I prefer to hire a pro for that very reason - peace of mind, knowing they will be cared for - unless its a friend you can absolutely trust.

Other option, find a friend who will let the kitties stay with them, perhaps in a spare bed or bathroom. A spare bathroom, while it sounds less than ideal, would be larger than most kennel cages.

If a kitty were to become ill, am sure you would not want it to go 4 nights without care.

"My boyfriend does not want anybody over to the house..."

Your boyfriend needs to man up and become part of the solution. Ask him what he wants to do.

Don't do it, IMO a whole day and night alone is already pushing it. The boyfriend needs to realize that cat safety trumps his aversion to having someone come check on them every day. We hire a cat sitter who is very reasonable and also checks in with us every day (via text) to let us know how the kitties are doing. Well worth it for the peace of mind.

Your cats really do need someone to come and check on them, clean the boxes, make sure they have fresh water and food, etc. Having pet sitters is part of having pets. I'm sorry, but your boyfriend needs to get over not wanting someone to come into the house. The cats are more important than whatever reason he could have for not wanting a pet sitter. Cats find it pretty stressful to be boarded or have to stay at a different house. They don't understand what's going on, why they've been taken from their home, etc. They have no reason to think they will ever see their home again, either. Boarding is not something to take lightly with most cats. Seriously, just get a pet sitter. If your boyfriend is nervous that someone could snoop, lock up whatever it is he's afraid people will find or see.

I own a boarding kennel. I stopped boarding cats because they do not do well under stress. The best would be to have them stay home and have some one come in. I tell cat people to call your vet, many of the hospital workers pick up extra money by sitting. If your vet employs them they should be responsible.