for light mtn biking (could be done on cross bike) try waterton canyon
there is over a 50 /50 chance you'll see bighorn sheep riding in the canyon
http://www.denverwater.org/Recreation/WatertonCanyon/
not challenging ride but very beautiful perhaps a good short ride for your first day to help you get used to altitude
here's another article on strange brew
http://www.denverpost.com/food/ci_15198853
reminder if you take your loop counterclockwise you get hills out of way earlier in the ride as you hit the foothills first and downtown last and you'll be following the bear creek and platte downstream and have the brewpubs closer to end of the ride