If you are short on time and want to get a quick hike in, here is an excellent list. I recommend the Serpents Trail for everyone. Serpents Trail was a part of the original road until the 1950's.

Mica Mine is a nice hike on a warm day. The canyon offers shade and multiple creek crossing. The geology is unique.

Lunch Loop is a must for Mountain Bikers and Hikers alike. Lunch Loop has many trails and those trails can connect to many more. It can be a bit overwhelming, so plan your route before leaving the trail head. I recommend not hiking this one alone.

Grand Mesa. If it is hot in the valley, go the Grand Mesa.