I like the "game" of having things sent to me. Perfecting something like that goes with my personality and if I miss it, I'll be creative about it, just as you explain.
I had film mailed to me constantly for three months along with other treats from friends. Other memebers of our group also got mail. It was never a problem.
Try to choose a place where you will be taking a rest day during the week or maybe Saturday to help ensure the post office will be open when you are there.
Try to choose a smaller town. General delivery mail goes to one post office, so if you have someone mail something to, say, Seattle, you may have to do some travelling to track it down. Not the case in a smaller town that has only one post office. My favorite mail story is from Browning, MN, which was a suggested mail stop. A worker at the post office made a welcome sign for everyone in our group that had mail and hung it on the front door.
Contact the USPS to find out how long they hold general delivery mail. Back in the day, it used to be two weeks. That is a pretty big window schedule-wise.