Yep, there are two parking lots at Ft. Wilderness. Just request a 2nd parking pass, and they can park in the overflow lot near the Outpost of Ft. Wilderness. If they are coming from the Magic Kingdom Toll Plaza, it is the 2nd entrance on the left. You can meet them up front, give them their ID cards, and they can transfer their stuff to your car to unload at the site, or just for a few minutes bring their card back to the site to unload.