Definitely load up the POI (Points of Interest) file from Mousesavers. My Garmin with maps from 2009/2010 had NO clue where certain things were inside of Disney--things like Winter Summerland and Fantasia Gardens Golf (which have both been there far longer than my maps!). Last year, the first time we went to play golf we wasted 20+ minutes with the false directions from the Garmin before I remembered I downloaded the mousesavers POI files. That took us right to the course.
Also, things change very rapidly in the Orlando area..even a map that is only a year or two out of date may not have the latest and greatest data.