First of all, that is not a dumb question!
I think you actually hit the nail on the head. Keep in mind that puppies are NOT
100% house trained until a year of age. Being only 7 months old, and in a relatively new (or different) environment is enough to upset the applecart.
She doesn't know where or how to ask to go out in those surroundings. She knows how to do it at home, but not on the road. That is normal. You need to literally double the number of times you would normally take her out, and stick to the basics of always using the same door, etc.
When you go there, are you the only one responsible for her requests or do others help out? Even if your other family members attempt to help, they don't know her signals, and she is still a puppy for all intents and purposes. Unlike a male dog, she is far less likely to be "marking", and far more likely to simply be overwhelmed and confused.
We went through the same thing with Oliver at the Lakehouse, even if we were the only ones there. Once he passed the age of 1, he knew enough to go to the door that he
wanted to exit, as opposed to the already perfectly constructed dog run located off of the garage. As soon as he would go to the door, we would rush him to the dog run.
7 months is still very young, and new environments are challenging. As I said, double the number of times you would normally put her out, and always use the same door! It really helps if other family members notice her even looking at the door and at the very least call for you to take her out. If you are on your own in that regard, it's easy to be distracted and not notice her cues.
The only dumb questions are the ones not asked, or the ones that are asked and answered over and over. This is the first time this particular question has arisen and it's a good one, especially for those who wish to travel with their dogs.
That's my experience and I hope it helps. I'm sure others will also have great tips to offer. Don't worry...you are still doing everything right!