In what would be typical West Colorado, Grand Junction has a lot of really good street spots. There's a park outside of Telluride in Ridgeway. But this time of year in Northwest Colorado you have to travel to skate.
Grand Junction is about the same temperature as Denver, so it should be melted and ready to skate. Also, there are all kinds of irrigation ditches to skate in the fall and winter.
But if I were you, I would drive down to Eerie outside of Denver and skate the new Street League park.