As usual, Thom is detailed and right on the facts.
We lived in Estes for 8 years but left in 2003. Have been back a couple of times but I new Thom would see this with correct and detailed info so I did not respond.
Last time there we stayed at Riverview and highly recommend it over any place in Estes itself. But you have the drive up and down the Big Thompson Canyon - not difficult but time consuming. I think they are still working on it after the last major flood but presume that is not a big issue - heard of a slight delay near Drake (about halfway up).
I have heard good things about Marys Lake since being run Estes Park - it used to be private.
Any of the others in town are a real "gotcha" - way overpriced for average rv parks. A couple of them used to be really great but changes in management (in some cases) and the almighty buck prevailed.