I was there when I was about 14 and my siblings were all younger, youngest about 4. We drove so went into the local towns, but it was quite a big campsite with a large pool and slides anyway so there's plenty to keep kids amused! I think there was a 'cinema' of sorts, and kids clubs. The market came once or twice a week. Basically, I don't remember being bored at all
We camped in our own tent at les mouettes in 2014. We had an enjoyable week despite pretty awful weather. Even when the sun came out it was cool and breezy. Pool complex is very good. Kids made friends on site so were happy.
Off site we enjoyed a wander around morlaix, got free bus to nearest resort of carantec which is a pretty little place with great beaches, went on a boat trip to a fort on an island nearby (fort taureau or something) and went to an ancient burial mound because I love ancient history. Spent lots of time eating fabulous Breton cakes and crepes whilst sheltering from the rain. I prefer south Brittany but we throught the area was worth a visit.
when we use to stay at a site in Benodet at lot of families based themselves at les mouttes at the end of their holiday for a few nights as it is close to Roscoff, i only ever heard good things about it