I've also got a Wii, though with only one Wiimote/nunchuk (one wired GCN controller, one off-brand wireless). But if Jiggles has us covered on that end, it may not be necessary for me to bring mine.
I also have a car (can fit five at the most), though my original plan was to park at the place I parked for Otakon and walk to the meetup and back. If I'm gonna be carting people around and we hang out Sunday too, then I'm gonna have to stay at somebody's place Saturday night, as I don't have the gas to drive to Baltimore and back twice.
Also, I don't know Baltimore too well, so if I drive, well... bring cellphones. In case.