Thanks for the responses. Perhaps I wasn't specific enough with my original post as I seem to have received the "use the search function please" responses. ;)
I have read the FAQ and the link provided previously many times. They are somewhat vague on details during the winter when the shuttle isn't running. All they mention is that private vehicles can enter the park. If my private vehicle is a 25 foot RV, will that be problematic? Areas of interest are miles apart in Zion. Can a 25 foot RV be parked at various areas of interest? Is there a parking lot at the places the shuttle normally travels to that we will be able to park a 25 foot RV since we can't take the shuttle around? Normally I would take the shuttle or even ride bikes to the various trailheads but those two options aren't possible in the winter.
These are all specific questions the FAQ's don't address and having never been there before I would like some advice from someone who has been and has driven a MH into the park in the winter. Thanks!