Costa Maya is WAY up north, a gorgeous resort, great beach: nice place to hang out & read. Also the tour operators will pick you up there, so diving & snorkeling are right at your door.
However, getting in and out of town has been a problem for some guests. I recently heard a couple complain that their flight got in after 3:00 and Costa Maya wouldn't pick them up.
Island Ferry will get you into town every 2 hours for $15 BZ one way (I think, I have my own boat).
There aren't many other restaurants nearby either except the one at the resort - Portofino has awesome food, but it's quite a hike...
You can rent a golf cart up there too, and get around the area easily, but it's about an hour ride into town, depending on how many bars you stop at on the way.