Roaring Forks use to be open 24 hours, but isn't anymore. I think their hours change according to the season though. Last summer (July 4th week), there were limited items available from the kitchen after 11pm. Before 11pm, the full menu was available. There were still plenty of people in there at that time, so my guess would be that it stayed open until at least 12 mid.
PS. Can you tell we are late night snack people?
We were there last week and RF is open until midnight each night, but the grill closes at 11pm. You can still get cold stuff and snacks until midnight.
I'm pretty sure that the hours don't change seasonally. Have a great time!