If you take bustang to Rocky Mountain National Park, you do not need a permit. So I took it from Denver to Bear lake road park n ride. I hiked to Sky Pond.

丹佛暑氣仍未休，山上風來已涼秋。搭得巴士上山去，國家公園任遨遊。 https://www.youtube.com/watch?v=T679v12kyws&t=38s