We are moving from Texas to Wisconsin. It is a 1330 mile trip. We will be stopping at 2 hotels along the way. Do you have any advice for traveling with a Boxer, a kitten, a Betta fish, and a 4 year old in a car-seat? As you can see we will have a full vehicle. I saw somewhere about people letting their cat travel loose with a litter box in the car. We got a carrier for safety and will need to make a few potty breaks along the way. Just looking for more input.
Can't pitch in on advice for dog/beta fish/kid, but can throw in my 2 cents for the cat.
Depending on the cat, if your cat is accustomed to car rides and frequent outings, and in fact likes it, this long journey may not be a problem for him. You mention that it is a kitten, how old is he/she? Kittens (but not extremely young ones) are more amenable to new experiences (and in fact kitten-hood is a good time to get them used to things they would otherwise hate in the future, like teeth brushing, going into the carrier, walking on a leash, being picked up, going to the vet, etc.) So depending on how old your kitten is, it may or may not be a good idea altogether to travel so long in the car with it.
From my experience, indoor only cats who are NOT used to car travel simply won't pee/poop even if you make pit stops during the drive. They will hold it in until they couldn't. And even once arrived at the hotel, the environment might be too foreign for them to feel comfortable enough to go to the bathroom. Same with eating/drinking. Cats are creatures of habits, I really can't emphasize how stressful venturing outside the home is for the cat. Obviously, there are some intrepid and well-adjusted cats that are the exception (and likely have been exposed to these kind or experiences since kitten-hood).
I don't think your alternative has to be giving up your cat. Since you are traveling inside the US, perhaps as your family drives to your new place, you can board your cat or leave your cat with relatives/friends. Once you are all settled in your new house, AND have moved all your cat's old stuff (bedding, rugs, toys, bowls, etc. anything with his/her scent on it) in the new house, you could fly with your cat to your new home (yes, I'm aware this means you will have to fly back and then fly with your cat again, and it can be costly). Domestically you can fly with your cat in-cabin for about $100 on most airlines. This will dramatically shorten the journey for your cat, and once he/she arrives everything would have been set up for him/her. So the whole trip would be less traumatic for the cat, and fewer unfamiliar places with unfamiliar scent.
Also, getting some Feliway (a spray / diffuser of cat pheromones) may help calm your cat while traveling. It doesn't work 100%, some cats don't respond to it, but it is something to try. A trip to the vet prior to long travel (in any form) may also be a good idea, just making sure that all is okay.
Good luck on that trip!
If you are sure you want to take them with you, do so. It is a long trip and a bit of a hassle to move pets over these kind of distances. If you decide not to take them with you, you can always try to get them a nice new (foster) home before you move.
For Dog & Cat:
Train both in using a harness. You need to be in control. Your cat will not like it. But not much choice here.
Have a good travel crate for each of them. That way you can drive without distraction or worry to your destination. Nothing worse then a cat or dog loose while you are traveling. If possible, introduce these to your pets and make them a good place to be. Due to cat claws I recommend a hard cover travel crate for them.
At each stop give them a change to drink, eat and relieve themselves. That means having kitty litter available.
If you know they are of a nervous disposition, visit a vet, explain the situation and ask for calming meds for the trip. A calm pet is a good pet for a trip this long.
Travel crate examples:
I see two options. Betta fish are not that expensive most places. And if yours were, you would probably know better then me how to transport it.
First is to just try and take it with you. A plastic container with 5 liters of water (~2 gallons) with some water plants and a lid will go a long way. Oxygen replenishment is a issue with water proofing. Open every hour or so? Food or oxygen in the water are not the problem here. If it doesn't get too warm or freeze, it might make it.
Second is to give it away to people who know how to keep one. And buy a new one at your destination. That long travel is not that good for fish.
4 year old:
You know that better than I ;) have fun!
I can speak from experience for driving with cats, but not for the other pets.
Having made many (20+) round-trips between Atlanta and Orlando (450 miles each way) with between 3 and 6 cats varying in age from 1-2 months to 2-3 years, there's a lot which depends on the capacity of the non-driving partner and the temperament of the cat and other pets.
Firstly, you will definitely want to make space for a litter box - preferably the one your cat is used to (if you have the space for it) and be prepared to make a sudden pit-stop to empty the litter if kitty drops a bomb.
It's entirely possible that he won't want to use it, as other answers have indicated, but in my experience some cats tend to find their bowels loosen 10-15 minutes after the journey starts, so if that happens you want it to happen in a litter box which you can easily clean.
I would also strongly recommend that you load kitty into the car in a crate which he is familiar with (so if you don't already have one I'd suggest you get one) and leave it with the door open (or detached) in your house for at least a few days (preferably a week or more) so that he can become familiar with it. It would probably be a good idea to place a blanket or pad inside during this time (with the hope that it'll pick up some of his scent) and leave it in for the journey to offer some small amount of familiarity.
You could also move his litter box into the crate during this time to get him used to the space.
Once the journey has started, and if he seems reasonably calm (don't expect a settled, happy cat - just not frantic), your non-driving partner could open the crate and let him out, but be prepared to make sure that he doesn't interfere with the driver.
It would also be a good idea to pack you car in such a way that little spaces (like under the seats, etc) are blocked off and that you'll be able to recapture him if & when necessary without having to search & dig too much.
Most of our cats quickly became settled on my wife's lap (sometimes taking turns, other times 3 at once) or they would find a small 'safe' space to curl up in.
You just need to try to make sure that any cat-accessible 'safe' spaces are also easily accessible by you, because you don't want kitty to be able to dart out of the car when you open the door at a pit-stop. Make sure that you either have a very firm hold on him, or put him back in the crate before opening a door.
I always tried to keep a bowl of water available in the crate (when we used one) - a large-ish bowl (to prevent tipping) with a little water (to prevent it sloshing over) with occasional top-ups throughout the journey seemed to work.
You could also offer a smaller bowl with some dry food, but he might not be interested in eating while the car is moving.