I live in MA and regularly drive on the Cape Cod National Seashore to surf and fish. I haven't had my new KJ out there yet, but have driven my stock ZJ and XJ out there hundreds of times so it should be the same. Wider tires would definitely help but aren't needed. I use BFG AT's and they work great-- the side lugs seem to act like paddles when aired down. All terrain's seem to float better than mud tires.
Air down to about 14 PSI. Makes a huge difference as far as flotation and saves a lot of wear and tear on the drive train. If the sand is really deep or soft go down to 12psi. I've never lost a bead. Carrying a compressor is a good idea. Whenever you see someone really stuck, they always have neglected to air down.
Carry a good tire preassure gauge.
Carry a small shovel, like an army surplus entrenching tool.
Make sure you have tow points and a good strap.
Carry a full size spare.
Carry a 12x12" or bigger board to put your jack on so it doesn't sink in the sand.
Stay in high range and use momentum. Crawling in low range sinks you fast.
I also carry 2 large "traction mats", actually rubber rectangular non-skid floor mats used on restaurant and bar floors. These fit nicely in the back of your Jeep and help protect the carpet. I have used these in sand, mud, and snow to self rescue. Same idea as the sand ladders you see on expedition Land Rovers.
Wash you Jeep really well when you get home!
Floor mats:
http://www.floormatworld.com/pagea3.html
Oversand vehicle equipment and driving tips from the National Park Service:
http://www.nps.gov/caco/activities/over ... ories.html
http://www.nps.gov/caco/activities/oversand/tips.html