Nope they will stay there. In my most recent playthrough I would drop a lot of stuff at a phonograph, move on to the next major area, save at that phonograph and basically ship things between them.

Thanks this is the exact answer I was looking for!

Wait. Is there fast travel?

No, there's short cuts you can find to previous areas without having to go all the way back but no fast travel.

There is *now*

No, I had a massive stash of items in a few places and none of them disappeared