M.R.
My older child was on a twin by 16 months, his younger brother will be switching very soon (he is 22 months and just decided he can climb out of the crib). I would minimize what he can play with in the room.
To switch my older child I started out by snuggling with him until he was asleep and gradually weaning him so I snuggled a few minutes and then sat on the floor stroking his head or holding his hand. Eventually I would snuggle, kiss him, and tell him mommy was watching him and I would sit in a rocking chair until he was asleep. He still sometimes gets up and plays and goofs with his brother (he is 3 1/2) but most nights things aren't too bad. There will always be bad nights. Adults don't get punished if we can't fall asleep, we just find something to do. Try to help him stay quiet and remind him that nighttime is for relaxing. If you have a fan or sound machine, try that. If the room is not safe, he is not safe in it, but if it is safe, relax and put him to bed a little bit earlier so he can get the playing out of his system.
(I should add that my 3 year old still asks mommy to snuggle for a bit and I try to take time for that--he won't want that much longer I'm sure!)