I am towards the beginning of the game and don't quite have the house in Megaton yet. I want to store stuff in this toolbox right outside the outcast outpost. It won't disappear if I leave it there for several days in-game time, will it?
I used the vending machine in the super duper mart as a safe for dozens of hours and nothing happened. So maybe those are safe, but I'd recommend what other people said, find a container, and make sure to keep multiple save files to make sure all your stuff doesn't disappear.
Thanks for the comments guys. I decided to go ahead and try this with stuff I'd *like* to keep, but if I lose it, it's not a huge deal. I wanted to do the Mothership Zeta DLC to gain a few levels so I can have enough skill points to disable the Megaton bomb and get the house. I'll check after the DLC to see if that stuff is still there.
I figure that spot that I chose should be fairly safe, since no enemies typically go there thanks to the Brotherhood of Steel protecting it. Unless the Brotherhood decides to raid the box since I didn't let them have ANYTHING after the Operation Anchorage DLC. Heh...