Great area all up Pingree Park Rd. The spots you can stay in without being bothered are all in the first mile or two. Good road, rather washboarded, but go slow and you'll be fine.
The first main area, and the top of the first hill is the best. Two areas of sites, and the one on the left as you go up has access to the rocks on the hill, which are from another world. Best sunset spot by far.
Farther up, there's a road, 127, off to the left with even more spots. The ones at the top of here have a veiw of the mountains on the north side of Estes park: Stormy, Evaline, the Mummy Range, etc.