I've camped AT the beach just not ON THE BEACH. Stay on established road ways and such might be best. If you do wish to try driving on the beach walk your intended route first. You want hard packed sand. If you have to cross a dune watch the incline at the top and both bottoms. You don't get caught at the top (remember Robin Williams in the movie) or have to plow thru at the bottoms. Plan how you'll go in and out. You might not have an option of a turn around which will require a back out. Plan the drive and drive the plan. Know the limitations of your emergency road service should you get stuck. Most will not pay for a tow if you are too far off established road ways. They will assist and getting someone out to help but you'll be footing the bill.
Bring a vacuum to help keep the amount of sand inside the coach to a minimum. A foot wash tub at the door will help. Unless your down in the surf the salt spray shouldn't be too bad but still give the coach a wash once you get home. Keep you awning rolled up whenever you leave the coach and at night. There's pretty much a continuous on or off shore breeze going that could without warning gust a bit and collapse the awing rails. If you have levelers, not sure how well the they will work in softer sand but I would treat them no different than camping on soft dirt.
We're in hurricane season and the storms coming off Cape Verde and out of the Caribbean Sea are starting to grow so keep an eye on what's happening thousands of miles away. The storms can roll up the coast quick so get out early if possible. Not all storms come from the sea side so watch their forecaste track. They won't be hurricanes by the time they reach the cape, either by sea or land, but they still have a lot of water and wind energy.
Good luck and have fun. Post an update when you get back. The Cape is on my bucket list.