My family and I just finished the Rio Grande trail last week. The trail was fantastic and the file that OTG provided was priceless!! Just wanted to add a few comments and pics. The trail is rated green which is mostly true, although there are a few spots that I might mention. My vehicle has a substantial amount of ground clearance and in 1 or 2 spots I needed it. You can take a lifted sprinter 4x4 but one of the last spots would be tricky. Not just the rocky trail portion but also the height and width of that section of the trail. The first spot to mention is The Agua Ramon Moutain as you leave the small town of Alpine.(perfect place for a refuel) This portion of the trail is green, but my wife and kids were uncomfortable here. It has a very steep climb, but mostly it's the severe drop-off on the driver's side for 2-3 miles, it's about a 1500ft sheer cliff, and the road has a slight tilt. It's no problem, just a heads up. The last portion of the trail that needs attention is the last portion, about a mile past the Rio Grand Reservoir. (We started at the New Mexico border and ended in Telluride heading West.) As we broke from an amazing camp right off the road the trail turned into a solid Blue trail. Very rocky, low-hanging trees, very narrow and steep. A lifted Tacoma was heading downhill and it took both of us almost an hour to shimmy past each other. (I had a camper trailer, the lady laughed and told me I was crazy bringing that thing up here!) We made though! All in all an amazing trial and must-do for everyone!!