Mine are 11 and 9, and since they were 3 and 5, we've done Eurocamp, specifically this site just outside Paris, which we've been to 5 times.
www.eurocamp.co.uk/campsites/paris/pa012-la-croix-du-vieux-pont/ataglance.html
DS2 is also Mr. Sociable and regularly befriends other children on the beach or in the pool. There's also a free kids club, and he ditched us several times in August to attend there. There's an adventure course type thing on site, which we utilised for the first time last year. DS1 went shooting with DH and MIL, DS2 went on the zip line and did archery with Kids Club (we paid €10 for that), and I had a go at the trapeze.
You can get to Paris in around an hour. Either by driving to Compiègne and getting the train or booking with the parc to go on their coach trip that runs once or twice a week. It's also an hour from Disney, which we did as a day trip the first time we went.
It's in a lovely little French town that is very French and unspoiled by tourists. Nearby (15-minute drive) is Pierrefonds, an incredible château that was used in the filming of Merlin. Children go in for free, and adults are about €8. That's a great day out as Pierrefonds is a pretty village, and there's a fantastic ice cream parlour with a shaded garden at the foot of the château.
Soissons is about a 30-minute drive away, which is pretty, and Compiègne is about 20 minutes away. Also, about 15 minutes away is the Armistice Clearing, where Germany surrendered in WW1 and France surrendered in WW2. It's a poignant place.
Last year, I took a hammock (bought from Aldi!), which I strung up outside our accommodation using the tree and decking, and spent a lot of time relaxing and reading in it.
I know you're not into resorts, nor are we, but we like the flexibility Eurocamp gives us of doing our own thing, but being somewhere that DS2 can make friends and they can have some freedom. DS1 spent half the week over at the football pitches.