This route connects the dirt road CR #116 with the rocky, rutted jeep road FS #505 (Caribou 4x4 trail) through to the old mining town of Eldora, then by pavement to Nederland, through town on street and bike path to some mellow singletrack at Mud Lake Open Space, then on Peak to Peak Highway and CR #130 back to Sourdough Trailhead. A very diverse ride.
Park at the Sourdough Trailhead parking lot. Exit the lot and turn left to follow CR #116 towards Rainbow Lakes. This dirt road starts smooth but gets rough and less maintained as it climbs. A little before Rainbow Lakes Trailhead, FS #505 drops down to the left and the ride becomes very rocky and narrower.
If you parked in Nederland and were riding higher pressure in your tires for the pavement stage, now's a good time to let some air out. The trail eventually becomes less rocky, but starts badly eroding, then crosses Caribou Creek at a sandy bottomed ford - generally rideable in the summer months.
From here, the trail is flat for a while and full of large puddles and ruts - a 4x4 playground. Usually a bike can ride around, but you may occasionally have to walk through the woods for a few feet to get around. The trail is now climbing. Stay on FS #505 when you get to the parking lot at the intersection with Caribou Road. Turn right to stay on FS #505 (also CR #128J). Follow the sign to Eldora.
The road now climbs steadily until it finally reaches a steep rocky pitch that I always have to walk. You arrive at a saddle near Mineral Mountain at around 10,300 feet. From here, follow FS #505 left and begin the long rocky descent into Eldora. The trail narrows and becomes rooty as well as rocky as it enters deeper forest.
In Eldora, turn right then drop two blocks left to Eldora Ave (CR #130) then turn left past the historic buildings onto pavement and downhill to Nederland. Wind through Nederland to the bike path that starts at the end of Jefferson St north of Peak to Peak Highway. Climb the switchbacks past the community center, across the highway again, down 6th St to the path up the creek to the Elementary School, through the parking lot and onto the singletrack on the other side of the entrance that leads down to the trails around Mud Lake.
Go right around the lake on Tungsten Loop
. Nice view of the lake here. From there, you can head directly to your next Peak to Peak segment at the parking area, or as I prefer, ride round the lake on the north, down across the creek and climb the meadows on more singletrack to the parking lot on CR #126. From there, drop the dirt CR #126 back down to paved Peak to Peak, a fun downhill.
Turn left on Peak to Peak and continue the descent. Then begin a big climb on the highway. Soon after the intersection with Sugarloaf Road, turn left onto CR #130 to get off the pavement again. This will roughly parallel Peak to Peak but with almost no traffic and better views. CR #130 rejoins Peak to Peak at the start of Switzerland Trail
For a truly epic ride, continue straight onto Switzerland Trail
for 25 more miles on Switzerland Trail Gold Hill Road Loop
back to your start. Or turn left on Peak to Peak Highway and ride the pavement for two easy miles back to CR #116 and Sourdough Trailhead Parking where you car awaits.
Many historic mine town buildings still stand and are in daily use in the town of Eldora, nearby Nederland has many services and a history museum.