The Peak to Peak Highway starts in the quasi-quaint gambling town of Black Hawk on CO-119 and tracks through the foothills to Estes Park. Unlike some of the Colorado Byways, this road is continuously paved and maintained throughout the year. The 55-mile stretch takes you through several small mountain communities, past Golden Gate Canyon State Park and through Arapaho and Roosevelt National Forests. The drive affords nice views of the Contenental Divide (on a clear day) but it was snowing the day we drove up, which is nice in its own way. 
The road is well populated and dotted with a variety of lodging opportunities, gas stations and other services.
Snowy days in the mountains offer lots in the way of interesting sights. The most common sights, like barns and old farming implements, take on a sort of surreal beauty. There is also some beauty of the more natural elements, rocks and trees and frozen lakes, to be seen as well. As always, know your own driving limitations with regard to snow and icy conditions. There are some fairly steep grades and sharp twists in the road that can be problematic even when the road is being maintained in winter.One of my favorite places to stop and snap a few pictures is the St Malo Retreat Center between Meeker Park and Allenspark. The chief point of interest here is the Chapel on the Rock, dedicated to St Catherine of Siena in 1936, which can be seen on the left side of the road as you head north. 
The architecture is elegant and simple and the dramatic height of its stone foundation on the east side is impressive. The looming presence of Mt Meeker in the background adds to the impact. The door is usually open during the day, but remember to respect those who have come to visit chapel for its primary function: to pray. For Catholics, this is a significant locale as the chapel was visited and blessed by Pope John Paul II in 1993.
The architecture is elegant and simple and the dramatic height of its stone foundation on the east side is impressive. The looming presence of Mt Meeker in the background adds to the impact. The door is usually open during the day, but remember to respect those who have come to visit chapel for its primary function: to pray. For Catholics, this is a significant locale as the chapel was visited and blessed by Pope John Paul II in 1993. The trailheads for Wild Basin, Long's Peak, Lily Lake and Twin Sisters Peak are all along the last stretch of the byway between Allenspark and Estes Park. These entry points to Rocky Mountain National Park have varying seasonal availability. Long's Peak is generally a technical climb between October and May. Other trails may only be open to snowshoers and crosscountry skiers. Check the RMNP website for information regarding trail closures.
Once you arrive in Estes Park (a great destination for touristy shopping excursions) you can return to Denver on a more direct route by taking US-36 back through Boulder. Between May and October (check the RMNP website for exact dates) you can continue on through the park on the Trail Ridge Road Byway and cross the Continental Divide on the nation's highest continuous paved road. It is closed in the winter.
Have fun!
