Summit County:

Day 1: Warm up day. Frisco (or Keystone or Breckenridge) to Copper or Vail Pass. From Frisco only 5 miles to Copper and another 6 to Vail Pass. Back down to Frisco. If you feel OK, go around Lake Dillon, up to Keystone and then up to Montezuma or Loveland Pass. If you still feel OK, go back to Frisco over Swan Mountain Rd. All of this is well over 50 miles. Bring your camera.

Day 2: Mt Evans. Drive through Eisenhower tunnel back toward Denver to Idaho Springs. Take the Mt Evans exit, take a right and park in the parking lot about 1/4 mile on the left. 27 miles later you'll be at 14k feet. If you are a bit tired from Day 1, you can drive up the road half way to Echo Lake and park there. Continue on bike. Coast ALL the way down. Bring your camera. 54 RT if you do the whole thing.

Day 3: Copper Triangle ride. Start at Copper Mountain. Up over Fremont pass and down into Leadville. Then over Tennessee pass over to Minturn. Then through Vail and up to Vail Pass. Back down the other side into Copper. 77 miles. Bring your camera. Optional: rest day.

Day 4. Hm. You'll be toast. I'd recommend you take a day off somewhere like day 3. If not, you could ride Hoosier Pass or Loveland Pass (if you didn't do it the first day), Independence Pass (from Leadville).

Mountain riding season is June to about October for most riding, but Mt Evans is a safe bet July/Aug.