In reply to Dave:
But did you ever have "lessons" Dave? Or did your kids ever have lessons? Of course there is a technique, but I find with classic it's quite easy to get into a groove and keep on going to the limit of your fitness (whatever that maybe). As long as your wax is working well it is a beautifully efficient way to travel, like a well tuned road bike on a smooth road - yes, over a day it completely knackers you, but in the moment it can feel almost effortless. Skate style is very different and even a hint of incline shows up my far from good technique, but somehow classic is just so nice and smooth, that's why kids to pensioners all do it perfectly happily. Although - of course you're right that if you want to race you gonna have to everything perfectly so that then it is just your fitness that determines your performance.
Henry - people here train on roller-skis or inline skates (with poles), although inline skates will only help you with skate style I guess. But there are classic style roller skis, although with the lack of bike paths in the UK choosing where to go could be the crux of that form of training.