If you are looking for intermediate to challenging type riding, I suggest you head up to some local favorite routes. Visit a local bike shop and ask for a map and suggested routes. You can go as slow as you need to and walk any obstacles that seem too difficult.
Biking, Sol Vista… stop in the bike shop at the base of the resort to rent equipment, get a map and ask for recommended trails based on your experience. You can go to the base of Sol Vista and jump on the lift to the top. Then choose a downhill trail that suits your ability. If you are acclimated to the higher altitudes and in good condition, you might like a long climb, jump on Natures Way from the base area, and take one of the fun downhill trails back down!
Bike Ride: Turn at CR 83, staying left at the “T” onto CR 84. Then take the first dirt road on the left just after the small bridge. Either park and ride from here or drive (slowly) a little further to the parking area on the left at the bottom of Hurd Peak Rd. An Intermediate ride would be to ride up Hurd Peak till you want to turn around or till you get to a rough camping area. You can look for the downhill single track from here or continue on the single tract in a slightly upward direction. When you get to a road, turn left and ride the road all the way back to your vehicle. This is a long loop.
Blue Sky Little Vasquez Loop
A nice loop to ski : Drive up Vasquez Rd and make the first left on Arapahoe Road. Continue past Viking Road to the dead end parking area at the National Forest. There are no signs that tell you this but locals call this Little Vasquez. Ski up a few hundred feet to Blue Sky on your right side. Turn right and stay on this for a nice climb till you get to a road. This is the Waterboard Road and you will turn left and stay on this wide road all the way back down to the parking lot!