I have never used RA for Pa. but have used it for other states with no issues. I have been told that the info.,sites lengths and pictures, is totally up to the state not RA. After twice finding myself in Fl. booked into sites that were not the advertised length I have had good luck calling the park and verifying the site length before I get there.
Fl. state parks are required to hold a certain percentage of sites available for walk-ups only. Supposedly the number varies from park to park. Once when calling ahead for a site on the spur of the moment I was told by the ranger that she could not tell me if she had a site available but if I got there "soon" there would probably be one. When I checked in she explained that they were not allowed to "reserve" a walk-up site even for a few hours ahead, it had to be truly a walk-up.