Hi Ritchie, welcome to the forum (and to motorhoming!).
I'm glad to see that you don't want to spend your days sitting in (or even outside) your van - neither do I!
One of the best ways to use a motorhome is to think of your overnight stops as just that - overnight stops. That means, the campsite (or Aire, or car park) isn't "the place where you have your holiday." You have your holiday at all the different places you visit during the day, doing or seeing whatever your particular passion is. That works, whether you're in the UK or on the Continent.
But where those other countries offer something more is in the welcome you'll find, and the facilities offered. In France, the country I know best, there are several big differences.
First, every town, and many villages, have good value campsites, often municipally owned, in convenient locations (not in the middle of nowhere!). And you'll nearly always find room without booking ahead, except on the most popular seaside ones in July/August.
Second, the network of "aires." I don't mean the motorway service areas (also called aires), I'm talking about the ones Jonno referred to, officially known as "aires de service camping-cars," of which there's one in most villages and towns. These are even cheaper, often free in fact, and most provide basic water, waste and toilet-emptying facilities. On the majority of these you can put your furniture out and enjoy the sunshine, but check any signs to be sure, or watch what others do. These Aires are nearly always very close to the centre of the town or village. You can find them from a book such as the one Jonno mentioned, or just look out for the signs as you travel (white square, blue outline, black silhouette of a motorhome). Very often, you'll find excellent (and cheap) bus, tram or train services from an aire or site into the town centre, so you'll rarely need to take your van into those congested places.
Even better, the French have a law which says a motorhome can legally park, including overnight, anywhere a car is allowed to. However, if you're taking advantage of that legal right, you mustn't put anything outside, or wind out your awning, or even use levelling ramps. Any of that would mean you were "camping," not "parking," and the local authorities ARE allowed to forbid that.
Oh, and many big tourist attractions have space designated in their car parks for motorhomes to stay overnight, so no worries about how you get from a campsite to what you want to see.
Not all Continental countries are quite as motorhome-friendly as France, but (IMO) all of them are more so than England - and most have an equivalent of Aires (the sign I described has become pretty well international).
Hope that is of some help, and reassures you that, while some people may choose to take other transport along, there's really no need to.
Come and join in the fun!