Hi Kimberly!
When my family sailed on the Disney Magic out of
Miami, we also flew into the Fort Lauderdale Airport. We rented a car at the airport and drove ourselves to the port. This was convenient for us, as we had to make a quick stop for toothpaste. Cruising out of the Port of Miami is slightly different than leaving from Port Canaveral, but nearly as easy.
When we cruise, my husband usually drops my daughters and I off with our luggage at the port. I check our luggage with the porters and go through security without him, while he returns the rental car and takes a shuttle back to the port. By the time he arrives back, the girls and I are usually through security and have checked in at the Disney Cruise Line desk. One thing to keep in mind, upon entering the Miami Cruise Terminal, each person must have their own passport in hand to enter, so while I usually keep my husband's passport when we are at Port Canaveral, he had to have it in Miami.
So, this is truly a personal decision for your family. If it seems easier and less stressful for you to keep the Disney Cruise Line transfers, then that is the best plan for you. If you would rather try renting a car and saving a bit of money, give it a try. There is also the option of taking a taxi from the airport to the terminal.
Good luck with the rest of your planning and please let me know if you have further cruising questions!
Happy Cruising, Tracy V.