I have a 4 hour layover at (MIA) then gonna connect to (CUN)?

My flight lands at Miami international at 6:55 am Miami time then I connect to another flight to Cancun that departs at 1:45 pm Miami time what can I do for almost 4 1/2 hours of layover, should I checkout South Beach or is it too far from the airposrt? I have to for sure be back at the airport by no later than 11:30 am to check in for my connecting flight or should I just stay in the airport bord as hell?