Actually, I was there last December and talked to the resort directly, and this is the way they told me to address packages ...
Disney's Port Orleans Resort - French Qtr
c/o Guest: YOUR NAME (Res #XXXXXXXX)
2201 Orleans Drive
Lake Buena Vista, FL 32830
United States
Phone: 407-934-5000
OR
Disney's Port Orleans Resort - Riverside
c/o Guest: YOUR NAME (Res #XXXXXXXX)
2201 Orleans Drive
Lake Buena Vista, FL 32830
United States
Phone: 407-934-5000
My packages (shipped to FQ) arrived perfectly and were waiting for me, but worth noting that the main package storage is at Riverside, so if you're picking up at FQ it may take them a while to bring them over from Riverside.
Hope that helps!