We'll be arriving on an AA flight from EZE quite early on a Friday morning and then heading back to LHR early evening on the same day.

Any tips on what we should do during these hours?

1) Should we just stay at MIA and hang in the lounge for 10-12 hours or so?
2) Take a shuttle/train/taxi (or something else into Miami and if so where to)?
3) The secret FT option:____________ (fill in the blank)?

Neither of us has been to Miami before and we'll have our carry on bags with us of course. Is there a place we can leave these at the airport OR do we need to bring them with us?

We're in J from EZE-MIA and MIA-LHR if it makes any difference in getting out and back in to the airport time wise...