I have actually used Payless a lot with no problems, although Payless has gotten poor ratings from the experts reporting in such places as Mousesavers.
Once I arrived somewhat early and they simply gave me the car early. Once I arrived somewhat early and they would only give me the car early if I upgraded (extra cost).
Payless is one of the companies that reserves the right not to rent to you if you decline their collision coverage and also do not have proff of collision ona car you own backa t home.
As far as their shuttle goes, Payless is on the way to Disney, not a backtrack. Leaving their lot, take a right (instead of their suggested left) and contineu down Frontage (becomes McCoy), then take two quick lefts at the end (Conway) to get on 528 (Beach Line) west to I-4 West to Disney.
Watch for the toll booth signs. At many locations you must "exit" the turnpike on the right to pay cash unless you have a Florida electronic tag (not an I-Zoom or EZ-Pass.) Also I strongly suggest getting a receipt.
Returning to airport via I-4 East to 528 East, get off 528 at its exit 9 (Tradeport). Left and cross under. (Nice cheap gas station right here.) Get into middle lane. Required right onto McCoy (becomes Frontage).