Sail mag recently posting this short story of 'shallow draft' cruising Sail-camping on a Hobie 16 | Sail Magazine On another occassion I did the same with a Louisiane 37 catamaran that drew 19 inches of water with the CB's up and the rudders kicked up. Come to think of it I took that same Louisiane 37 down along the backside of the outer islands of Cape Hatteras, NC (there were times we were pulling the boat along while walking the shallows....what a great trip that was). I'm sure there are not many boats of that size that have ever made that trip.
....and from another posting I made on this forum http://www.yachtforums.com/forums/123583-post41.html
It all depends on where you cruise. If the Florida keys, if you can keep the draft at 4' you can enjoy the bayside of the keys and some pretty nice spots. Along most of the east coast, up to Long Island, you won't have to worry about shoaling, tides, etc... Same in the Bahamas. 4' opens many areas you can't go with a 6' draft.