DS has a Sleepyhead so that's been handy because we took it with us so he was still in the Sleepyhead even if everything else was unfamiliar! He woke up in the night a bit more often than usual for the first two trips, but was ok on the third one. Don't know why, maybe teething or leaps in development were factors. On all the trips naps were a struggle (but they can be at home too). If I remember rightly I think he did go back to sleeping better when we got home.
I guess the important thing is to try and stick to the bedtime rituals and general routine as much as possible when you're away. I think it's also ok to just do what you have to do to help them get some sleep, even if it means adjusting or retraining them a bit when you get home.
The advice seems to be not to start any kind of sleep training just before going on holiday, so we are waiting until we get back from our next (and final, for the time being!) trip. For now we are just rocking instead of feeding to sleep at bedtime - it went smoothly again tonight, yay! 
I do need to stop putting him the Sleepyhead soon, as he's too big for it now, but I'm not quite sure when to start the process - before or after holiday... it would be good not to have to take it with us, but then if it helps him sleep while we're there it would be worth it... tricky.