Palo Duro Canyon is the second largest canyon in the US, and is located 20 miles south of Amarillo TX, our midway stop between Bentonville and Durango. Palo Duro has a 30 mile loop with terrain ranging from undulating single track thru juniper forest to rock garden climbs on loose rock, with tight switchbacks thrown in to foster humility. The total elevation gain is in excess of 1500', with a big chunk of that on the Comanche Trail.
The half dozen main trails are well marked, but there are dozens of offshoots that aren't on any map. If you plan to explore, take extra water. The dry desert air can quickly leave you feeling dehydrated.
For the most part the trails are easy and we saw a lot of people on rental bikes. Over half the trails are multi-use, and a ranger told us that conflicts are becoming a problem, especially during the season. But towards the lower end the trails get more technical and steeper, and thus more fun. Right?
I wouldn't consider this trail system a destination, but it is midway between east coast and west coast trails, so it would make a good rest break from driving.
Elevation gain > 1000'