I have a student who went there for 2 summers...about 10 years ago.
Her mother (who trains standardbreds) said that the riding program was safe, but very very very basic and recreational.
The other camp activities were fun and they had a good experience there.... when the girl became more "serious" about riding, she went to a different camp that had a more "horse show" oriented riding program. Not as much fun, but better instruction, and oportunity to show at local and rated hunter shows...
I did not go to Camp Rim Rock but went for several summers to the horse camp at Camp Friendship. It was fabulous and very intensive, the riding was great (two lessons a day, 6 days a week) and I learned a lot. That was over a decade ago but they are still going strong. It's located in Palmyra, VA.
I have a coworker whose daughter's gone there for at least a half dozen years -- She'll be a CIT next summer --
They LOVE this camp -- From all I've heard it is a well run program with an emphasis on safety -- Riding program has BHS certified instructors, but seems to have a recreational focus -- They do offer one week at the beginning of the summer that is riding intensive --
The camp appears to keep the horses long term ... unlike some camps that pick up horses and dump them at auctions at the end of the season --
"I never mind if an adult uses safety stirrups." GM
I have a student that went there this summer and loved it. She's a beginning intermediate rider - w/t/c/crossrail jumper, and she didn't have any complaints that it was too basic, nor was it too advanced. I gave her mother information on her riding level to give to the instructors so they would know what she was doing at home and what her abilities were.