All of the above is too much work for me. I buy boxes in multiples of five at Staples. With tax they come out to 0.63 cents each. I mail a 1 lb. bag of rocks to myself, using another property as the return address. The boxes become starter for the fireplace in the winter months.
One day when I was working on landscaping, I simple put all the rocks in one place and then bundled into 1lb freezer bags. I have 25 of them I use over and over
Because I live on a street with an odd name and do the same 50 or 60 post offices over and over, I just say that I mail a gift to my daughter and grandson anytime I'm on the road because I miss them so much if questioned by the clerk. I shop a lot of resort towns so it works.
Everytime I'm convinced they've figured me out, they mess up so I know it's just paranoia.
I'm sure my post office knows what's going on as I Iive in a tiny rural town. They havent said anything but I get exceptional customer service. They often save up the 20 or so identical boxes they have for me at any given time at the post office until I'm home so the tweakers don't steal them. I never asked them to do that.