R.J.
Playpen time!
Or... if there's a closet big enough for the mattress... either a babygate... or for $10 you can buy eyelet screws and a big mesh laundry bag and create a babygate. My mum used to do that with us when we were travelling, since she couldn't bring a gate or playpen with her. Baby got a dresser drawer, toddler got the closet crib. Older kids on futons. Just us (littlest one in a backpack) and the dog backpacking/train-treking all over asia.