Anyone have experience with SetVehicle or maybe Idles? I'm using SetVehicle for my carriage mod, but when I put a follower on the carriage and then use an idle to seat her, she doesn't stay in her seat, she randomly starts standing in the front of the carriage with her feet in the ground (default location for everyone)... for some reason, she forgets to stay seated during the carriage ride. She may stay properly seated for 10 minutes, then suddenly be in the front, or she may only stay seated for a few minutes.

Anyone have thoughts/ideas?

Temporarily assign her to an alias in a quest with high priority. The alias should have one of the "DoNothing" AI packages. Perhaps the "StayOnCart" package.

EDIT:
Did some testing and yes, using the "StayOnCart" package works for me. Weird thing though, when I used SetVehicle with 3 or more actors to the cart, it flew a couple hundred feet in the air and started spinning/shaking like crazy.