Just to follow up on this... we ended up staying at Sea Dreams Cabanas (the 2 bedroom unit upstairs from the windsurfing shop). We rented from Bobbi at Caye Caulker Accomodations and both her and Haywood (the owner of the house) were wonderful to deal with.

Only Costa Maya and Caye Caulker condos are closer to the split and neither offered the two bedrooms we were looking for.