I spent a few weeks in Colorado last summer, and was thoroughly disgusted with the fishing conditions. I grew up fly fishing all over the front range, but haven't fished there in nearly two decades - so I was looking forward to revisiting some of the places I fished as a kid. I didn't have a whole lot of time for it - but figured I would be able to get a few hours in one afternoon & the following morning.
Unfortunately, the Rocky Mountain Anglers Club (or some similarly named group) has bought access rights to all the water I wanted to revisit. I couldn't get in to enjoy any of it. I'm not sure how extensive the problem is - but check their website to see if they have the area you are considering locked down. If they do - prepare to pay upwards of $500 to a private organization for the *privilege* of accessing public water.
If no one here can give you specific advice - try finding the phone number of a fly shop in the Silverton area & ask them for some tips (then stop in and buy a few flies from them . . .).
Good luck - and here's hoping you are more successful than I was.
"Life is meant to be enjoyed, not endured" ~someone