I've done that "miserable" layover in MIA more than once. For me, what makes it bearable is the purchase of a day pass at the AA Admirals Club; I think it's well worth the cost. They have lovely private bathrooms where you can shower and change (they provide towels, hair dryer, etc.), free food, lots of comfy seating for reading or using electronics. It's quite refreshing after a redeye from the West Coast.
I look forward to more of your reports as you have time.
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