It is worth nothing that the TM post office is located in the same canvas building as the TM store, and the packages are frequently stored in the store area.
What that means is that it is sometimes possible to do package pick-up after hours. This is handy if you want your package after 4 pm, or on a Sunday. Just ask nicely, and you might get lucky. I just picked up a package there a couple weeks ago, and it was stored on a shelf above the store cash register.