Go to Chama, NM. It will have cool temps in July and is a good central location to southern CO and northern NM. You can:
Ride the train, swim/fish/ relax at the lakes (there are two in the area), drive up to Pagosa Springs or over to Taos. Take a river float trip. Drive through Georgia O'Keefe country. State parks at the lake have first come first serve and reservation sites. RV park in town but I have not stayed there. None of that may appeal to a 16 yr old but the local kids hang at the lake beaches on most weekends.
It is only a couple of hours from Chama to Red River.