Hey!
First off, you should ask your vet for sedatives to keep your dog calm during the trip. They might prescribe Benadryl, or Gravol, or something else to make your dog sleepy, or they might prescribe an anti-anxiety or something similar. Either way, it would help a lot!
The day before you leave, or the morning of, take your dog for a run. The longer the better; you want to tire your dog out and make sure they do all their business before you start driving.
If your dog has a crate and is crate trained, I would recommend driving at least some of the time in that. Not only does it keep your dog contained, but it helps them feel secure because it’s familiar and cozy.
Keep the noise levels (wind from the windows, music) and temperature mild and boring. If your dog is easily stressed, keeping things calm is the easiest way to go. My dog gets freaked out by the sunroof, so consider keeping that closed too.
Bring lots of water and stop often for water breaks and to stretch the leggies and pee. When I roadtrip with Marlo, we stop every two hours or so. It’s more often than I would stop if I was alone, but it keeps her happy and prevents her from getting stiff.
Feed a small meal at least an hour or two before you leave, and then offer another small meal later in the day if your dog doesn’t look too stressed or nauseous. Don’t worry if your dog refuses to eat – one or two skipped meals won’t kill her. Lots of dogs won’t eat when they are anxious.
For staying in a hotel, I don’t find anything terribly different than staying at a friend’s house. Try to get a corner room if possible – that minimizes the people walking outside your door. Don’t leave your dog in the room alone, because that’s scary for your dog. Take her out often to pee, and offer her lots of water (I find anxiety tends to make dogs thirstier). It’s very likely that she won’t settle the first night in a hotel – it’s to be expected. Just comfort and reassure her the best you can. It’s all very scary to a dog, she doesn’t understand what’s going on. If you have more nights in hotels, those will probably be a bit easier.
Keep an updated copy of your vet records (you probably got one with your receipt at your last appointment), a recent photo and description of your dog, information like her license number or distinguishing characteristics, and the names and contact info of emergency contacts (you and someone else, preferably someone not on the trip). If the worst happens and either a) you lose her or b) she has to go to the vet, you’ll have all that information handy. I keep mine in an envelope in the glove box marked “MARLO VET RECORDS I.C.E.” so they are easy to find.
Here are some links for roadtripping with dogs. X, X, X, and X. The above points are from my own experiences, with my own (admittedly awesome in the car) dog. I hope this helps a bit, and feel free to ask more questions! -C