I haven't ever been asked about weight, it's possible we could be a few lbs over once in a while, it hasn't been a problem.
Assateague is one of the most outstanding TC experiences imaginable. We have camped in the Bullpen for as much as three weeks, coming off only to dump and for water and supplies, mostly in the fall.
The Assateague Mobil Sportsfishermans Association, our wonderful fishing club, has been a prime mover in keeping the beach open for all of us. There have been many attempts to close off 4X4 travel there. By working with the officials and offering solutions to their problems, a system that is satisfactory to both us, the public, and the NPS folks, we are all able to fully enjoy this fabulous natural treasure. If you have any inkling of trying the beach bit, DO IT ! And consider joining AMSA. It is not expensive and well worth the effort. See Ya on the sand!