I (Jared) am 6'4" so maneuvering can be cramped at times. Sleeping isn't hard for me because both the poptop and the back bench (when folded down) offer decent sized beds. If you are doing it with another person, I do recommend it being someone you have a very strong relationship with.

I would guess the hardest things for most would be: safety concerns, the lack of storage space for possessions, and not having a private bathroom.