Miami?

[CityKid]

Hi! I'm going to be in Miami for a weekend in October for my sister's bachelorette party, and I was wondering what kind of suggestions people might have for general tourism. I'm taking a red eye and landing in Miami on a Friday at 7:35am and planning to meet up with my sister in the early evening. What is there to do? Because of my budget, I'll be limited to public transit. I've already figured out how to get to MetroRail from the airport. From there are there any historical sites worth seeing? Any particularly beautiful walks? Charming pedestrian friendly neighborhoods? Once my sister arrives I'll probably be laying out on the beach with a cocktail in my hand until my flight home so I am not worried about seeing the beach. Also, if anyone has any suggestions for places to go out, they'd be much appreciated. Thanks in advance!