I mailed a package to SSR for our stay a couple of weeks ago. I sent down all of our liquids, such as shampoo/conditioner, suntan lotion, shaving cream, deodorant, toothpaste etc. I also sent down some extra laundry detergent, dryer sheets and coffee filters.
By sending this package ahead of time, we were able to pack up for our stay on just carry-on bags and that made traveling much easier for our family.
I'm not sure of the exact weight of the package, but it cost approximately $12 to send.
I will do it again on our next stay.