Thank you both!
Yesterday, before I posted, I had a lengthy conversation with my friend about many of the concerns y'all have brought up (I was shocked when she told me about her daughter's plan given the winters). I shared the campgroundreviews website, told her about the MT winters (including needing to use an insulated rig skirt, make it a 4-seasons rig, etc..) and how difficult it can be to even find an open park. They only tent camp so she was very grateful for the information. Her daughter has done a lot of research on the conversion van part of the project, but much less so on the realities of winter living in such a cold climate. I suggested they consider encouraging her to rent a room in a house for the cold months since budget is a concern (I suspect that's why no dorm).
I was hoping there was a hidden gem (like Jim & Mary's in Missoula), but it sounds like campgroundreviews is pretty comprehensive.
She's a smart girl with a solid head on her shoulders who's been wise about the steps she's taken so far (lots of research and conversations with people who have done conversions). Hopefully, their trip to visit at the end of this month will provide enough realistic perspective that their daughter will reconsider her plans.