Thanks for this info.
Great job.
Missed a couple key points.
I keep beach towels on lap and car seats. Also a roll of paper towels and big ziplock bags handy to clean up accidents. They do poop occasionally when they first get going.
I have never had one escape. They just know not to get out unless I prompt them. Especially the two indoor younger ones. The older one is just too lazy to get out!
It’s all about getting them used to the ride.