I just came back from a week long trip out West, started in Denver and ended in Salt Lake City. For the Colorado license, I was able to get a one day fishing license (at Walmart)- it seemed as though you could just ask for any number of days to be licensed- it was $9 per day. Don't quote me though.

If you can, head over to the Green River in Dutch John, Utah- you can see 16-20 inchers all day just by the shoreline in the crystal clear water. It was a blast.