We do this on most of our trips. Alamo will send its shuttle to pick you up from your resort or one of the parks. You do have to call them to reserve the pick-up time and tell them how many in your party. I would advise giving them about 24 hours' notice, even if you call from home. Be at the meeting spot at least 5 minutes earlier than the time they give you.
They have maps there if you need some assistance getting around.
When you drop off the car, the shuttle can take you back to your resort or drop you at a theme park. If you want to be dropped at Magic Kingdom, they will leave you at the TTC.