We just did it on our last Dec. trip. I ordered the AP vouchers through the
DVC site (for the discount). Upon arrival to the AKV, we went over to the AK park guest services window. Validated our AP vouchers and bought the TIW card right there as well. I stressed out over the process of it all prior to our trip as well (since we had ressies at Boma that night that I wanted to use the card for.) It was Easy Peasy!