Thanks for the feedback as I incorporated much of what was said. We spent a day in Arches and did the hike to Delicate Arch first. It made for some great photos up close. For the altitude, heat, and distance my son did pretty well. I only had to carry him on my back the last 1/4 mile. He was a little worn out when we went to Landscape Arch but got his energy back to run up the sand hill by the entrance to the trail. Rather than attempt a Canyonlands hike we did a 2 hour Hummer tour around Moab and a 4 hour jet boat tour up the Colorado River into the National Park. Canyonlands by Night and Day was the company.