We're staying with a friend near West Palm Beach after our stay at WDW. Part of the trip will be to drive through Miami and down to Key Largo for a couple of days. I have visions of having coffee one morning at a cafe in Miami, and raw oysters at a Margaritaville-type restaurant while watching a sunset in Key Largo. Anyone have any suggestions?

That is a place where you just go with the flow. I tell you that the mood changes once you've gotten over the bridge, just stop at that first gas station and you'll see. I mean they have Wyland portraits on the sides of Kmart down there!! If you could make it to Key West... ahh the sunsets there will break your heart they are so beautiful, and the feeling of relaxed excitement it palpable. Have fun, you'll have no choice!! 
Islamorada Fish Co. is the Bestest restaurant ever. My DH and I fell in love with that place years ago when we first moved to Florida... and now that we live in NY it is a memory i visit quite often. The dock, the staff, the water, the view, the FOOD