The thing is, other than moving, I can only think of three other things that will actually move you: using a "warp" such as the sewer entrance/exit, using Drag as a zombie, or being dumped as a corpse. Ah, and the "Go to Serling" button, but that should only appear in one of the old areas.
As for custom weapons, I dunno, ye olde Slime is the one who does that. From what I understand, you can just take the stats of whatever weapon you want (that you actually have) and rename it to what you want and what you want it to show when you use it.