Hi Mobius,
If I were you, I'd try to put a plan together, starting with your 'must do's'!
If you can always get to the parks early, and make use of the early starts only available to those staying on site!
Like others have said, if you can, try and see a little more than just Disney! If you're into music, then try and eat at the Hard Rock Cafe at Universal?!
Sea World is also a great day out!
If you're into shopping, and like brand names at discounted prices, you must visit the Premium Outlets (not too far from DTD). If you join the online VIP club, you'll get extra discounts! My DS and DH got some great Timberlands (about $40 less 20% disount). If you like Abercrombie and Fitch, you'll find it the Florida Mall!
I think Linx buses are probably your cheapest way of getting about, but use the I Trolley if you are in that area (think it runs from Festival Bay area at the top of I drive, down to the Premium Outlets - I think?).
Hope this helps a bit?
Tracy