There were fifth wheels and HD trucks aplenty the last time we were at FB. That was before we bought our 5ver and we had a smaller Trailmanor. But there was an Arctic Fox a couple spots down and the guy had a Dodge HD truck. He filled my ear with the wonders of both his truck and 5ver.
But that being said FB was very tight, even with our smaller TT we were just a couple feet from the next campers. We could hear everything that was said in the TT next to us. If we had slides I don't know if we could have put them out. I didn't notice that some sites were bigger, maybe in the back section. We were in the area nearest the road and I didn't look at the other area further in.
So there were lots of 5vers in the CG and trucks were parked helter-skelter. But maybe they've tightened up the rules. This was three years ago when we were there last time.
BK