Dustin, he was a big help in planning our trip^^^
I can attest to the fact that you don't want camp at the Rock Run site on a weekend. When we got there on Friday night, there were a dozen people there. This was April when it was still pretty chilly. Now that it's nice, I expect it gets used more heavily. If I was planning another trip, I'd try to schedule my night at that site on a weekday.
Even if you don't get that site though, there are other options for a great campsite close by.
Hope you have a great trip. I really enjoyed the loop and am sure I'll be back.