We took our son to England when he was 6mths and he wasn't really too bad. Your son will most likely be too big for the cots, Xander only just fit in on the way home at 7 months old, and they really are a hassle. You have to remove them every time the seatbelt light comes on, so we'd find that he'd just settle down and then we'd have to get him up again. It was good at meal times though as we could sit him in it and eat without having to juggle him around.
You will probably be told off for putting him on the floor - they really don't like it. It's considered a flight risk, kind of like leaving your onboard luggage in the wrong spot!!
Ask for your meals to be delivered at different times, they'll put one away for you if you ask and then warm it when you're ready. Ring the flight assistant bell as many times as you need to! They really don't mind helping out and if they have some quiet time will probably take him off your hands for a little while so you can stretch in peace.
You can take your pram with you until the very last minute. They take them from you at the gate and load them on last. It can be a hassle collecting them at the end of the flight but we found it very helpful.
Also, if you have a stop over anywhere, ask your travel agent to organise a courtesy car to take you to the gate you need if it's different to the one you land in. We stopped in Dubai and 30 minutes to rush from gate 3 to gate 42! You don't get the pram off for stopovers and we had a tonne of hand luggage!
You might be pleasantly surprised by the flight, my son loved the background hum of the engines and slept for ages.
No advice for when you get there, I had very little sleep for 4 weeks and my husband ended up sleeping on the couch so I could sleep with our son!
Good luck and sorry this is so long
Dette, DS 06.03, DS 10.04, DD 03.06 & Due Sept 07!