Hyatt Grand Cypress has free shuttles to the parks but they only operate 2x a day - so you may want to check that out if you don't want to drive over. Rooms were recently renovated - to mixed reviews.
RE: Costco / Hyatt check (gift) certificates - apparently its an item that is being discontinued - so go and buy some soon if you want them - also, there are reports that some properties are being very picky in terms of the rates that you can use these on - YMMV.
