Thanks everyone. I can't seem to get through to the SOG hertz to ask if they have a shuttle.
The Kissimmee location is a good idea, but I got a rate for the Hertz at SOG that was just too good to pass up. It was weird, but it's actually much cheaper for me to rent from SOG and return to MCO than to simply pick the car up at MCO (over $200 for the week if you can believe it), so I figure I'll take ME and then get my car after we settle in.