Well, he crawled in there himself. We turned some of our lower level cabinets into toy cabinets for Jett, only now they are empty. He loves to crawl into them and move the toys out so he can be secluded.
His puzzles have been in there tidy and put up, but he opened several of them on his own and spread all the pieces out. I just let him go. My house may never bee picked up, but this boy can entertain himself for sure.