On a 2 day I usually go as far as St. George's Caye and back with a stop in Caye Caulker. On the front side of St. George's there's a couple mangrove islands to the north, take the dinghy through the one with the deepest channel (about 2-3'), head north and you'll find a huge expanse of sand bottom about 2' feet deep. You can body surf and walk for miles there.