Yes, the seasonality seemes to be due to lack of snow removal. There simply isn't space to move snow and allow for cars to enter or park. You should call in advance before visiting during early spring or late fall.
Call and ask frequently, think theres an unofficial list
Yes they do have seasonal sites.... I hope to have one someday.... that will have to wait for me for some years...lol
Thanks! Your answer is awaiting moderation.