I spent the summer in Estes Park years ago while I was in college. I rode my bike all over the town and in the park. Trail Ridge Road is an awesome ride. I would ride up Trail Ridge Road to the Trail Ridge Store and then down Fall River Road back to Estes Park. There is also a nice bike shop there called Colorado Bicycling Adventures, they should be able to help you with anything that you need!! Have a great time and definitely eat at the Sweet Basilico Cafe, it's AWESOME!!