Any campfire that has an item inside on slot #7,8,9 (the last three) actually retains that item for every player-made campfire.
So far, i've only stored raw meat on slots 7, 8, and 9, but I've noticed that my campfire that I made two towns over, still had the same stored raw meat. SURE SAVED ME A LOT OF TIME though.
I think the same thing applies with non-player made AND player-made workbenches too -- put an item inside on the new slots, and it may retain it for you throughout all workbenches. I can't confirm but I stored a Paint Brush and 800 Wood inside, and found myself looking at it on Dwalls' Class Made Trader NPC inside.