For those speaking of can't imagine not taking a trip without your dog, what about taking a trip with a new dog that you don't know that well? Which is the situation with the OP - they're thinking of getting a new dog right before their trip. Not an old friend who has been with them.
I take my dogs all the time - that's a lot of the reason I got my RV - but I started them slowly with the RV, getting them used to it, used to rules that are different from home, etc. In addition, I already knew them very well and knew potential issues with personality, fears, etc. I can't imagine taking a dog I've only had a short time and heading off on a big trip with them.