Beautiful Trails and Falls, Barebones Campgrounds
My girlfriend and I camped at Gorges State Park for a few days in October of 2017. The trails are excellent and they were in great condition when we visited. The waterfalls are beautiful and it isn't a very strenuous hike to Rainbow Falls.
Camping seems to be hit or miss. The campsites aren't bad, but during our stay the privy pit was nearly unusable, so we dug our own. The access road to the campsite trail was closed as well, so the hike to the campsite from the parking lot felt closer to 3 miles. Given the lack of amenities and the distance to the Raymond Fisher campgrounds, I'd advise that you snag one of the primitive backcountry sites instead. They are situated along the main trail to Rainbow Falls, and almost every backcountry site was in a nice spot with easy access to the stream. Be aware that many of these backcountry sites are directly adjacent to the trail, and hikers will probably pass by your campsite.
If you are camping, expect bears. I don't know if this is still an issue, but we had a bear messing with our stuff every night. It didn't exactly bother us, but we did have to hang our trash and food far from the campsite while we slept. It made us a little nervous because we were the only campers there and you are miles from your car, but it didn't come close enough to our tent to really frighten us.
That being said, we had an incredible time and would definitely return. Despite being in a state park campground it still felt very secluded, and we felt that all the set backs made it more of an adventure.