There will probably be a poster or signage as to wher ethe local supermarche is
you will find it's probably an Intermarche or Lidl or Netto or Monoprix
IF you are lucky you could be near a L'Clerc , Auchan, or Continent

We're just back today from Chateau Des Ormes. We left on Sunday morning and took our time coming back up the road.
There's a small shop on site but it's expensive. Dol itself has a Lidl, a Super-U, a Hyper Champion and an Intermarche. Towards St Malo there is a huge Cora Hypermarket and apparently also a Carrefour but we never found it.
The market in Dol is on a Saturday and it was good. There is also a smaller market in St Leonard (about 1km from the site) on a Sunday and it was really just a smaller version of the Dol one. There are posters around the area for the Wednesday night market at Mont Dol but apart from a big stall selling Crocs there wasn't anything different there.

We were at Chateau Des Ormes for 17 nights and we managed 2 trips to the pool and one to the beach in that time as the weather wasn't up to much. We were in a Keycamp Villanova and were glad not to be in a tent as the ground got very muddy and drivers of bigger cars were getting stuck getting out of their pitches.

My girls are 6 and 3 so perhaps the things we did won't have the same appeal to your boys but I'll tell you anyway. The one recommendation I will make is that if you have a roofbox, take it off as many of the car parks we used had a height limit of 1.85m which is lower than a standard car plus box (I've tried and the box is covered in yellow paint to prove it!).
We did a day in St Malo and walked round the walls. On the way in, follow signs for Centre Ville and then pick up the Navette Bus signs. It costs 2.50 Euros to park the car and then a free bus drops you just outside the old town. St Malo also has a big aquarium with a submarine ride at the end and that was a full afternoon out.
We went to Mont St Michel. On the way there you pass Alligator Bay and if your boys like reptiles it's worth a visit. We spent over 2 1/2 hours going round it.
Dinard is pretty but apart from the beach we weren't very impressed. Dinan has lots of little shops and a pretty old centre.

I hope that helps. I'll probably remember more when I get over today's 400 odd mile drive.

Thanks for your reply. I'm sorry the weather was poor, it is my biggest fear at the moment, I need some sun on my back to recharge my batteries!
Any more tips you can think of would be most welcomed, this will be the 1st time we have tried this kind of holiday, we too are going with Keycamp in a Villanova. Our normal 'summer' holiday would be a hotel in a hot resort, but we are used to camping in this country as well.
I'm a fisherman and my youngest is also very keen and wants to take some fishing tackle. Did you see many people fishing and if so did it appear to be any good?

Thanks Again....

I wasn't aware of people fishing but the site is big and the lake is very long (like a blocked off river) and is divided by an access road for the golf course. The part nearest the centre of the park is the boating pond and any fishing would presumably be done in the further away part.

I've just been on the Canvas Holidays website and they have a video on there of Chateau Des Ormes (we're beginning to look at next summer's holiday!). These things are always biased but the guy they interview on it speaks very positively about the fishing.

We found driving on the site to be a nightmare because there were pedestrians and bikes everywhere in the middle of the road. It's by far the worst site we've been on for suicidal pedestrians and cyclists. I nearly ran down a cyclist who emerged from behind a hedge, failing to stop at a give way.