Christmas Road Travel – 10 Weeks

I have a 10 week old Brussels griff who has been doing pretty good with potty/crate training so far – she is 85% going outside, 10% on a pee pad and about 5% of the time on the floor. We are going to be traveling for Christmas about 4.5 hours from home and I’m so worried about potty breaks on the road. Has anyone traveled this far with a new puppy and what did you do if they are not fully vaccinated yet?

My vet was pretty unhelpful in the suggestions department so any advice would be so appreciated!