M.F.
We've encountered going to sleep issues with our 2 yr old too. He went from totally peaceful bedtimes to crying, back to peacefulness, etc. Now at 2 1/2 he's back to peaceful and we're soo glad!
I'd suggest finding a way to "wean" him off your presence at bed time. You'll really enjoy his ability to go to sleep independently once you have the new baby (actually, you'll NEED him to do it independently!). Check out the book "Good night, sleep tight" by Kim West.
Also, you might bring in a baby gate to keep him in his room. You're at a good place to begin implementing the last phase of sleep independence in the book, which is "job checks" after you put him to bed. Rather than sit outside his door (which is part of her method, so you're right on track), tell him you'll come back and check on him after you do something. We do this with our son and it has worked like a charm to keep him in his room after bed time (he also falls asleep with the door open, then we close it when he's aslepp). I leave and say "I need to brush my teeth, I'll check on you when I'm done," then go brush your teeth, then poke your head in and say "I'm checking on you, are you ok?"
Then you might fold some laundry, then take a break in 5 min, etc.
I've gradually increased the "check-in" times to where I don't check in for 20 or 30 minutes. Long enough to take a shower of have a chat with my husband.
This way, if it takes an hour for him to fall asleep, I haven't lost an hour to nothing but waiting and waiting.
At first he did have trouble staying in his room, which is why we used the baby gate. I told him I'd leave the gate down when he could stay in his room. We would start the process with no gate and say, "It's bed time, you need to stay in your room. If you come out, I'll put the gate up." He tested that our for a few weeks or so. He got really mad about the gate every time, but we said "I'm sorry, I have to put the gate up when you come out" and stuck to it and now he stays in his room and the gate just leans against the wall in the hallway as a reminder for him.
About half-way through this process we started asking him if he wanted the gate on or off. Of course he'd say "I want it off!" so we'd say, "I will leave it off if you stay in your room." It was sort of a positive twist on our earlier statement, and he was ready to try to comply. He had a few more instances where he pooped out of the room, but that's all.
Also, we decided in the begninning that his room would be the boundary rather than his bed. Now he might get down and come to the doorway, or get a toy or a book, but he always gets back on his bed to go to sleep.