We stay at shades of green as well. I'm not sure what time you'll have to leave, but if the bus comes later in the afternoon I have a suggestion! My family always spends our last day before we have to leave for the airport at Downtown Disney. We have a huge lunch to keep us full on the plane at one of the restaurants and do a little shopping!
We always rent a car while we're down there, but we've been known to take the SoG buses around Disney when it's more convenient. I know that the hotel has a bus that goes to DTD and back. Like a PP said, the hotel will hold your luggage until you leave.