We have never actually done this, but had a few trips planned out that included this model. We were planning on a few days at the park, then checking out of the hotel and storing our luggage for an afternoon at disney springs. Bus back to the hotel to grab luggage and head to the airport. We fly Southwest, so we would fly Orlando to Ft. Lauderdale.
Often when cruising out of Miami we stay in Ft. Lauderdale the night before and uber in to the port in the morning (only for sailings that leave on weekends to avoid work traffic and commutes). Many of the Ft. Lauderdale hotels are nicer and cheaper. Other times we uber to Miami straight after our flight and stay at the Intercontinental and take a short 5 minute uber to the port the next day!
Definitely possible and can be a pleasant experience, I just wouldn't try to pack too much in on your travel day. This will allow you to be flexible if your travel plans get delayed and will allow you to recuperate some before starting your next part of your trip!
I think it would be a little more challenging with a rental car vs an uber, but definitely still possible and enjoyable!