Hi Jen
We don't have bedtime snacks, we have tea at 5:30 ish then bedtime is 7:00 and he has a drink of milk just before getting into bed.
My rule is basically no chasing around, loud play after tea. We generally finish tea, go in the playroom and play with cars or something. Then we have a couple of books. Then we get his drink ready and take that upstairs, get his pyjamas out, have a bath, massage his cream in, have a drink then bed.
By this time he is fighting to keep his eyes open.
As far as PU/PD goes, when I need to, I just do PD because PU winds him up more! I lay him down and say lie down time for sleep. Then he gets up so I lie him down and we do this until he's flagging a bit, then next time I lay him down, I put a hand on his hip and he generally stays there. As long as he's putting some effort into sleep, I leave my hand there until he's almost nodded off, I gently remove it and stand next to his cot. Just before he goes off completely, I leave the room and stand just outside for a few minutes.
That all makes it sound easy but if you crack it once, when you have hiccups - holidays, teeth etc - you just do it the same way you did before, they realise what you are doing and it works more quickly.
I hope this helps.