Patty,
While I do not know of any road map on the Walt Disney World Website, there is another website that might help. Visit
www.WillCAD.org. This gentleman's personal site has scans of several valuable maps, including park maps, resort maps, and a road map for all of the Walt Disney World property (or at least the parts that a visitor would be allowed on).
Just click on "Disney World" and then "WDW Maps". When you get to that next page, click on "Miscellaneous Venues" and you will see a map titled "WDW Property Map". Select the Adobe PDF version and you can get a great color map (useful, if not pretty) that can show you the driving directions around the "World". I print this out for my trips every time!
By the way, odds are that your thought of going to the Animal Kingdom Lodge by car rather than the bus-transfer-bus method is a GREAT one. I once went to the expense of cabbing it there, just to avoid all the hassles and so I would not waste an hour of my time!
Have a magical vacation!