I always enjoy a trip over to Caye Caulker,only a 22min. water taxi ride inside the reef, when you get there have lunch at the Rainbow over the water then walk down to the split for one of the most gorgeous veiws you'll see in Belize.
In San Pedro rent a gas cart & head north across the new bridge & stop by the Palapa Bar & Coco loco on the way back. Very nice views .
Try to get on a roof top for a good view of S.P. especially at sunset.