We drove from Orlando to Miami with our rental car after flying into and out of Orlando, and cruised out of Miami. Took us about 4 or so hours, stopping once on the way down for food, once on way back for food and gas. Used the turnpike, as I heard Route 95 into Miami was to be avoided at all costs. With my sun pass I could use the turnpike’s no stop lanes to pay, just paid a little bit more than if I had that other Florida road pass, but much cheaper than paying cash, and having to stop.
And was was great to use that fee to drive road, as no traffic on it on the two days we used it. We parked at port, as was nice to be able to arrive and go as we wanted. We left around 8am on the way down, and was back in Orlando by lunchtime on way back. Since we had an evening flight home, we enjoyed lunch in the parks and more park fun before returning the car.
Your choice of transportation , but I would do a drive to the Miami port from the Orlando area again. Though I don’t mind driving. Drove a rental from Ft. L to KW and back, after staying a week in KW. Flew in to Ft L in morning, and had an late afternoon flight back. We enjoyed some beach time, and grabbed lunch before returning the rental. Now that SW flies into Miami, I’ll price the two airports if we want to go to KW again. Same with cruising out of Miami.