If an individual dealer organized a drive-away for a group of retail customers, they picked them up at Willow Cottage. There are a number of photos in 1947-49 issues of KAISER-FRAZER DEALER NEWS showing it; there are also photos of customer groups getrting on planes (a couple of them charters) to go to Willow Run for pick-up of their cars.
You can get more information on the Willow Cottage delivery program by checking out the topic on the KFOCI HANDBOOK CD that members get when they join the KFOCI. It's a perk for joining the club & is part of New Member Information.