Not far into town, a 20 minute walk along the beach. maybe 10 minutes from a big store...
the restaurant at Banyan Bay has an incredible view. sits right on the waters edge. we have eaten there several times, its always been quite good.
Check with Ian Andersons for cave tubing: //AmbergrisCaye.com/pages/town/cavetubing.html
they sure gave us a great time. Its possible to do like Xunantunich and the zoo the same day. I'd check out Lamanai from San Pedro, its a great one day trip. Theres links to info at: //AmbergrisCaye.com/tours/