A.V.
There is something called a crib tent you could try. They aren't exactly cheap and my son learned how to un-zip really quick. When we put him in a big boy bed, we put a gate up at his door and babyproofed his room to the max. That has seemed to work. He doesn't have any toys in there really, only a bookshelf. Sometimes he'd 'read' to himself, but other then that he stays in bed. This way he can't get up and wander around the house by himself.