I know that Yellowstone becomes a snowmobiling destination and a lot of others places are closed. Things are a bit different during the winter time. What are some good national parks for us to try and hit across the US this winter? Probably looking at Washington DC first and then heading west. Maybe some good hot springs?

Might be a bit late to respond but Bruce Canyon NP is really nice in winter, Acadia is really good too! Can't really go wrong with Yellowstone, but it's pretty packed in my experience.