You could buy some earplugs and let him scream a few mornings til he gets the idea. He won't hurt himself. How about a gate instead of closing his door? Maybe that wouldn't make him feel isolated, unless he climbs that, too. Also, when my first was waking up early, I used to put a snack in his room (after he went to sleep, obviously) for him when he woke up. It kept him occupied for awhile and I slept a little longer. You could try a sippy with some watered down juice, graham crackers, raisins, cut grapes, goldfish, whatever. You could also push his bedtime back a little, as suggested. Blackout curtains help, too. Just tell him, "it's still night--go back to sleep". Good luck.