We're down to once a month from every two weeks of mail forwarding. We have been using the same UPS Store in FL that has a physical street address since Jan 2005 before we went fulltime.
If I know something has arrived I can call them and get an early shipment. Otherwise, they have the current campground address or if the campground doesn't allow direct delivery - a local UPS Store address to receive them. Any boxes ordered from Amazon, etc are sent directly to the campground office. I have tracking #'s and can tell when pkgs have arrived.