Speaking as someone who has transported all @neepheid's basses to a bash, I would concur with his assessment of "Don't bring everything".
The one very small advantage of bringing everything, including a full top box, is that when you do pop into a rather decent guitar shop in Birmingham for the first time in nine months, you are limited to only buying anything smaller than a box of matches as there is simply no space for anything larger, thereby saving money. I'm not bitter about this at all. Nope, it's not a problem at all, it's all behind me now.
Rob