If you want to fish smaller streams with lots of bushes and plant life, a 6' long 3 or 4 wt is ideal. Use WF floating line, about a 6' tapered leader and some 5X or 6X tippet to save your leader. That time of year I'd probably make sure to have plenty of Elk Hair Caddis, Stimulators, Hoppers, Fore-N-Aft gnat patterns as well as Prince Nymphs, WD-40s, Hare's Ear, and Pheasant Tails to drop below the dry fly. Paflytyer is going to be a better source of info for the lakes than I will be since we have so few in NM where the fly fishing is worth a darn.
For the non-fly fisher, worm and bobber works ok sometimes. Tight-lining off the bottom usually gives better results. I would add some Powerbait and salmon eggs to the bait list as well.
Make sure you buy your license beforehand unless you plan to stop in a tackle/bait/fly shop or Wal-Mart as soon as you get to Colorado. It's very easy to get it online. I've done it several times.