We've done the drive from WDW to Ft Myers in about 3.5 hours. My parents spend the winter in Bonita Springs, which is about 25 minutes south of the Ft Myers airport.
In the past few years they have built a very nice modern terminal, and the airport is very easy to get to, get around, and navigate. Most car rentals are on-site, and you can walk to the terminal after returning.
This does not apply to you, since you'll be departing from RSW, but the thing that my parents love is the 'cell phone lot'. They arrive, and park in this lot. We'll call from the plane once we land, and get the OK to turn on cell phones, to let them know we've arrived. We'll call again when we have our bags. We get outside, and they are pulling up. Throw the bags in the car, hop in, and we're on our way.
It's really a great little airport.