Sure, the maps in Cancun & Cozumel Directions are good, but I do have some space constraints.
The good people at Can-Do Maps, however, can make maps as big as they like. They do really excellent fold-out maps to all the major beach towns, even showing building outlines and restaurant and hotel locations. They’re very handy if you’re considering a certain resort or rental place and want to find out just where you’ll be in relation to everything else.
And the reason I’m mentioning them here (they get a nod in the book, p. 32) is that they’ve expanded their offerings. In addition to Cancun, Playa del Carmen, Cozumel, Isla Mujeres, and the whole Riviera Maya (including Tulum), they’re now doing a map for the Chichen Itza area, and one for Cozumel’s reefs.
Check ‘em out before your trip–they’re perfect for getting the lay of the land.