I don’t pull a big rig but I think its self evident that the bigger one is the more difficult it is to maneuver tight places and fit in others. The key, though, is where you want to go. If you are happy with commercial parks and well developed camping locations the length should not be a problem. If you like the scenic roads and less developed scenic areas, then that size will likely be a severe handicap.
I can’t make a flat statement, but I suspect a very large amount of the state parks would be off limits, too. It’s really a tradeoff between size and comfort and ability to go where you like. Sort of a you can’t have your cake and eat it too type thing. Even 30’would be far too restrictive for me, but as said where you want to go is key.