Essentially, the two of you will be stuck on a deserted island for like 3 months. All powers of said comic book character will be removed for the entirety of your stay (except for healing factor if he or she has one.) No way of contacting the rest of the world.
For me, I'd probably want to be around Nightwing. Dude was trained by one of the best survivalists in the DC universe and probably the easiest to get along with in the Bat Family.