B.W.
I would definately suggest a baby gate or maybe even to shut the door to his room so that at least he can't get into anything that could possibly harm him. My daughter is 19 months old now and we switched her to a toddler bed about a month ago and she did surprisingly well, she always sleeps with her bedroom door shut so I did not have to worry about her leaving her room after I went to bed. The first night that we put her to bed she got out of the bed two times, I put her back to bed and firmly told her that she had to go to night night. The next day at nap time she only got out of bed one time and I told her firmly again that she had to go to night night, since then she has not gotten out of bed until after I open her door when she wakes up and then she comes out of her room. If you have having a lot of problems then you may have to go back to the crib for a little bit. But again I would have some sort of barricade so that he cannot at least leave his room such as shutting the door or putting up a gate. Hope this is helpful.