Denver has 650 miles of bike trails so most areas are reasonable access to commuter routes
over 25,000 people participate in bike to work day
here is a online map
http://www.denvergov.org/Portals/482...keMapPage1.pdf
When I moved to Denver 3 yrs ago
one of the first things I did on my house hunting was stop at REI (or bicycle village or any other bike shop
you can find) and for about $5 pick up hard copy Denver Biking map put out by the Denver bike touring club
www.dbtc.org
Every night after house hunting we'd look up locations of houses we liked on the bike route map.
To me the online map was too cumberson for that task.
(We ended up 1 mile from Bear Creek Trail)
As you go West you'll be getting closer to foothills and front range as you go East you'll
be getting closer to the plains. That said most of the major "River" or "Creek" trails ie: Platte, Bear Creek, Clear Creek, Cherry Creek and Highland Canal are fairly flat. C470 Trail has some hills.
Best of luck you may find like I did the only mistake I made was not moving to greater denver sooner