Whatever your length, wherever you go please know that lying about your actual length is never, ever acceptable. I'm sure all of us, if we were being honest, myself included, would love to have an RV that is a bit to a lot larger than what we have but...
Buy what you want, hopefully what you can live with but lying about it makes you someone that no one really wants to be. As noted many length restrictions are based not just on the site length but but on the access roads in and out. Not only do you risk damaging your RV on overhanging trees, encroaching boulders etc. you know you do not belong in a 30' site with a 30'+ RV. additionally you likely will creat problems for fellow campers.
I have seen access roads partially to fully blocked by folks who simply did not even come close to fitting into their site with their RV/TV encroaching onto the access road. That might work until a neighbor has a heart attack at O'dark thirty and emergency vehicles can't get in {and God help you if that happens}. :S
Years ago when I was attending San Diego State a professor brought in a guest lecturer to discuss integrity, honor etc., as I recall he was a retired judge. He droned on for nearly an hour stressing that it was never, ever acceptable to lie. He pointed out that integrity is like virginity... once it is gone it is gone forever. Fnally in conclusion he hit this point one last time wrapping up his lecture with the following:
You must remember that it is never acceptable to lie... unless someone asks you to help them move.
:B