How do you get them to the hotel?
I camp with two cats, two large dogs and a parrot. I have an SUV. The parrot rides in a celtei "bird backpack" in the passenger seat. The dogs and cats ride in the backseats and/or cargo area (I switch out putting the third row seat up or down). The litter box is placed in the back. I use the crystal type litter - it absorbs liquid the best and is easier to vaccuum up if spilt.
Neither of my cats like riding in a carrier (Looney2 has ripped through one before). I always keep the carriers in the vehicle, but I leave them open so they can go in and out.
My cats are good about not trying to get under my feet in the car. If they did that, I would put up a gate separator to keep them in the back.
If your cats ride well in carriers, I would keep them confined during the drive. In that case, use a plastic container with secure lid for the catbox. It can ride in the truck bed and you can bring it into the truck at rest stops and let each cat out to use it. At the end of the rest stop, put the lid on and return it to the truck bed.
If they won't ride in the carriers, then get two boxes that will fit on the floor of the backseat. Cover the backseat with a soft comforter and let the cats relax. If they "accident" outside the boxes, it will be on the comforter that can get washed. If cloth seats, lay a plastic tablecloth under the comforter to stop leaking.
If you have a camper shell and a window that opens from the cab to the truck bed, you can lay out bedding in the truck bed with a cat box and let them ride back there. The open window will allow the area to be heated or cooled AND lets you hear the cats for signs of distress. It also allows the cats to climb into the backseat as they like.
Always have your cats in a harness while on the road. And have a tag on the harness that includes your cell phone number AND the license plates of your truck and trailer. If a cat gets loose, this will give someone the ability to find you even if there is no cell service available.
With harnesses, there are two types of cats: one that never has a problem; and one that can and will back out of any harness (the "backer upper"). I have one of each type. Looney1 never fights the harness. I can attach a nylon tether to it and let him go in and out of the trailer all he wants. When he reaches the end of the tether, he goes another direction. Looney2 will back out of any harness as soon as he feels the tension. With him I have him wear two harnesses now. One has the ID tag attached. The 2nd gets attached to the leash (he doesn't get tethered). If he backs out of the one attached to the leash, he still has a harness and ID tag.
In the suv, they always have their leashes attached. That way I can easily grab the leash if they try to escape. Every time I get back in the suv, I count heads,and make sure everyone is accounted for before I drive off.
Once we stop for the day, the cats go into the trailer. They see it as another room of their home. They love looking out the windows and seeing the world. I never leave the windows open enough so that one of the cats could rip open the screen and get out. I have been replacing the regular screens with the heavier pet screening. A cat can still claw through it, but it holds up better than the regular stuff. I also never leave just the screen door closed. If the cats are in the camper, the door is securely closed - no exceptions.
Absolutely practice harness and leash walking at home. Never let the cats outside without being on a leash (or tether if the cat isn't a "backer upper"). Learn how your cats handle the leash in different situations - with people around, with cars driving by, in wide open spaces, in rocky spaces, and so on. The more you know how the cats react, the better you can keep them safe.
If a cat is a " backer upper", never let them outside (harness and leash or not) if you can't give them 100 percent of your attention. They can back out of a harness in a second and don't need to be scared to do so.
I leave their dry food out 24/7, but feed canned twice a day. This is specifically so that I can use dinner and breakfast as a lure for an escaped cat. They know and expect canned so when it's dinnertime I can call them and they will come.
With Looney2, he gets a bit skittish sometimes. If he gets loose, he will run from me. He also loves to cuddle and get tummy rubs. So I have taught him to come with the trigger "let's cuddle". At home, he will come to me and show his tummy for rubbing when I say that. It is a daily event. Out camping, if he gets loose, I can get him to come to me by sitting quietly and saying "let's cuddle" - he won't come until he's tired of exploring, but it will get him to come to me instead of my trying to chase him. With Looney1, he's Mr Social, so he will come back as,soon as he tires of exploring. They rarely get loose, but when they do, it is very stressful, so the more enticements to convince them to come to me the better.
I enjoy having my cats go with me. They enjoy it too. And with the camper, I can leave them inside while I go hiking, etc and not worry that housecleaning will accidentally let them loose. I always make sure the camper door(s) is locked to prevent a nosy person from opening it while I'm not there.
I also have a folding crate that can fit a cat box and the two cats - just in case I need them confined for any length of time.
