Ran Caribou on 8/26/17. 2 stock 3rd gen 4Runners (one with a locker, one without). 3-5 rating is pretty accurate due to inclines getting muddy and the very narrow section in Eldora. A couple spots offered some nice 3 wheel action and 1 - 1.5 feet water. Scenery is gorgeous! There was some disagreement as to which end to start at as we ran in to 1 vehicle starting from Eldora (he had to reverse dow to let 5 down). The narrow section down into Eldora has NOWHERE to turn around or back up if you are going down hill. It would be nice to have a sign to tell people where to start. We ran from Nederland to Eldora and it was awesome until the traffic jam. Camping: there are designated, dispersed camping spots (beautiful ones).