Getting to PO-Riverside from Courtyard by Marriott's Dollar rent-a-car location?

[whozit]

We'll be flying in to MCO and spending some time in the area before checking in to PO-Riverside. Decided to rent from Dollar so we'll have wheels, then check in at Riverside and unload luggage, then drive over to turn car in at Dollar's location at the Courtyard by Marriott near DD. We'll utilize WDW transportation for the rest of the trip. It sounds like the Marriott is walking distance to DD, we're thinking that we can just walk to DD and later take the boat (or bus) back to the resort. Any other suggestions? Does anyone know if Dollar has a shuttle at that location that would run us back over to RIverside?