RV Park reviews is pretty much the best review site, with Trip Advisor probably the next best. I take ALL photos with a grain of salt, since they are nothing more than an attempt to confirm the photographers position. The photos on the websites and other photos provided by the park ownership should always show the park in the best light. The only value you can place on those photos is if the park looks crappy in those photos, it probably is crappy. As for the fact that most of those park provided photos show people at play and the like, that is advertising. They post those photos for the same reason beer advertisers show people have a great time, and don't show some drunk fat slob, in his doublewide, beating his wife because she didn't make him a baloney sandwich.
As for photos by guests, I trust them even less. Those photos are also taken to prove their point. Heck, what is to say they are even actual photos taken at that park? I could go to the Ritz and toss a few pieces of toilet paper on the ground, take a photo and legitimately post a review saying this is what my room looked like. Just don't say you were the one who trashed it. They are of no value to me, whatsoever.