I shipped a box to my resort ahead of time with no problem. I did call the resort first to verify that they would accept it. They said no problem and they gave me the address to ship it to (it was slightly different than the address shown on my reservation, although either address may have worked). They told me to address it to: Resort Guest your name here Arrival date : mm/dd/yy then put in the resort name and address. When I checked in, they had a note in my file that they were holding a package for me and offered to bring it out to me or have bell services deliver it to the room.
I sent my box by UPS ground, that was cheaper than USPS (later I saw on one of the posts on this site that the USPS doesnt deliver to the resorts, but UPS, FedEx and someone else does, you might check with your resort to find out who delivers to them). I shipped my box so that it arrived 3 days before we left home, that way I could use the tracking number and confirm that the package arrived and have the name of the person who accepted it
.I figured if there was problem, UPS would have a couple of days to locate the package before I left home (it arrived on schedule, no problem).
Shipping the items ahead worked out great for me.