Nice one, Jane.
I'll echo what the others say about touring, though my experience is a bit limited: we did the Forest Way in Sussex from Groombridge to East Grinstead and back the other week in half term, staying overnight in a Travel Inn in East Grinstead.
It's only 15 miles or so each way (we did a bit of the Worth Way too) so I confess it hardly counts as a "tour" .. but we had the Little-LCs with us (6yo and 9yo) meaning our range and speed were both a bit limited. Still, they thought it was high adventure staying out the night with our bikes and taking all our stuff with us, the Elder Little-LC insisted on carrying all her own stuff: Pj's, teddy, toothbrush, change of clothes and so on.
We did some other rides later in the week (from home) and managed to squeeze 20 miles out of them one day with no obvious ill effects, totalling 71 miles over 5 days. We're hoping to track down a route with a couple of nights out next year, and building up their stamina in the hopes of having them ready to do the "Avenue Verte" London to Paris once it's complete. Course, we have to pick the roads we let them ride on with care due to their age, especially the younger one, but they're getting there.
The Forest Way is all off road, though we did some road work at either end and I agree with others that cycling is an ideal pace at which to see the countryside: plenty of time to look around, unlike a car, but faster than walking so you can cover a bit of ground. Even at the Little-LC's typical average of 7mph.
Sorry, I ended up hijacking your thread to tell of my family's exploits.