If you go to the UPS website and go to the calculate shipping section you will be able to figure out what day is best for you to ship the item and see when it would get there and an estimated price. For example, when we went in May, my check in was a Sunday so I needed my package to get there on the Fri.(no deliveries on the weekend) So on the UPS website it said if it was shipped on the Tues before it would get there on Fri, gauranteed. It only ended up costing about $10-15. I was able to track it online. UPS gives you that info. Since we weren't leaving until Sun, I was able to see that it got delivered on that Fri. and I printed out that info from online and took it with me.
As far as what to put on the box. I would always inclue the ressie#. Don't see what the security issue would be?
We put the resort name and address then the name the ressie was under, the ressie#, and check in date. We wrote it on all sides of the box. No need to call the resort ahead of time. They have a room where they keep all the deliveries so you have to ask for it when you check in. They brought it to our room when we were in there.