Well, the good news is, an Insight tail extension is easy to remove. With my 13 attachment points, it took 8 minutes to remove the tail extension, and 14 minutes to bolt all the factory tail pieces on: bumper cover, taillights, wheel skirts. Even after I add details like illumination, we should be looking at under half an hour to switch it out. So this is the kind of thing you could hang in the garage most of the time, and install for long trips. Unless your commute is a long trip, in which case you'd best just leave it on, eh?
Also, I got my heat exchanger seat cover sewn together, and my 12V pump is wired through the rear wiper motor switch.
I'll test that one out as I hit the road tomorrow.