Your right about the Euro caravans, and it amazes me to find that people manage to live in them! On my last site, there was a couple full timing in a VW Camper, now that is tight!!
There are some narrow and twisty roads over here, but actually it's not that bad, I regularly take large rigs in and around the centre of London, and as long as you don't stray off the main routes, it's okay. And most car drivers tend to give you a bit of space
I haven't had the experience of driving on your roads, but know even the minor ones are bigger than main ours, but I suppose it's all down to what your used to