If you don't mind German (or subtitles) there is a hilarious documentary on YouTube about one of the biggest drug sellers on SilkRoad named „Pfandleiher“ from Bavaria: https://www.youtube.com/watch?v=frdpQF4bVJ4
He talks about his „setup“ (old car repair shop), routine to drive to different mailboxes, etc. Got busted when meeting with people offline from Austria to sell larger volume. German police got curious when they read in Mexican internet forums that the most advanced drug seller is located in Germany with 3 day shipping to Mexico.