How does Mialo do with the 4 hour drive? Does he travel calmly or does he get agitated?
I travel back and forth between my home and my mother's, some 420 miles away, several times a year. That's at least a 7-hour drive if everything goes smoothly. When things don't go smoothly, as in major traffic and construction delays, it's been known to take up to 18 hours.
I usually put my cats in carriers for the trip, and if there are no undue delays, they're fine just staying in the carriers for the 7-8 hour drive. If it ends up being longer than that, I try offering them water at a rest stop, though they're usually too stressed to drink. If it gets longer than about 12 hours, I feed them small amounts of food. That can be tricky. Most of my cats are good travelers, but I have one who invariably gets carsick even on short drives to the vet. If, once she's vomited and gotten it over with, I stop and clean out her carrier, she usually doesn't vomit again. But if I feed her, then she very well might. If you already have planned overnight stops, I don't think Mialo should need to be fed in the car. Wait until you get to the hotel. And in the mornings, feed him as early as you can, so he has as much time as possible to digest before you get on the road again.
Once I tried putting several cats together in a big dog crate, with a litter box and a supposedly nontippable water bowl. Result: MESS!
On the other hand, using a carrier that's big enough to accommodate the cat plus a small litter box (try a disposable aluminum foil baking tray of the right size to fit in your carrier), and NOT putting any water in the carrier, can make the cat more comfortable and make your cleanup job easier upon arrival.
I think Mialo should be fine if, each time you stop to eat, drink, or use a restroom, you offer Mialo access to water and a litter box. If I'm going to buy gas, then go inside the convenience store and use the restroom and maybe buy a snack, I put down water for the animals first. That way they have the maximum amount of time in a parked, non-moving vehicle to calm down, decide if they're thirsty, have a drink, and go potty before I'm finished with my business and ready to start driving again.
I don't know about specific brands of harnesses. I have a bunch of different ones that I've accumulated over the years. If it says it won't put pressure on the cat's neck, that's a good thing. Just make sure it's secure. A breakaway collar is safer for a cat who's going to be left unattended while wearing it, because if the cat is already running loose anyway, it's better for the cat to lose the collar and continue running loose than to be caught by the collar and strangle. But if the cat is not going to be unattended, you're going to be with him all the time he's wearing the harness, then getting caught is not an issue. If the cat snags his harness on something, you'll be there to notice and unsnag him before he strangles. So in that case it's more important that it *not* break, because if the cat gets stuck you'll be there to unstick him, but if he breaks free of the harness, he could run off and be killed. I'd go with a harness rather than a collar, and make sure that if the cat does something suicidal like jump out an open car window while you're standing outside pumping gas, he'll just hang awkwardly by his armpits until you retrieve him, instead of either slipping out of a non-secure harness and taking off running for parts unknown, or breaking his neck on a collar. (Yes, I've had a harnessed cat hang herself out the car window at a gas station. She was indignant but uninjured.)
Good luck with your move!
