Hi
I have been going to France for the past few summers now - and love it.
Before you start booking through the big companies for park holidays -try a bit of research for independent rentals. Some places have a collection of gites around a central pool. If there are a couple of young families there then it would be more than enough for your toddler to play with.
Have a look on Chez Nous, Owners Direct and HomeAway.
But if you do want a park then the big companies websites do give a lot of information. You can then find out more about each campsite f rom reviews on camping websites separately - to find out just how good they really are.
We have only done the sites twice. The first time was when we took our boys to France. Me, DH, my DS, his two DSs. This was 6 years ago - so they would have been umm....8-12 years old.
I chose Brittany - as it wasn't too long a drive. It was a Keycamp holiday -and the site was Le Ranolien, nr Perros Guirec. It was quite a large campsite - and there was enough for the kids to go off and do. HOwever I don't know about younger children.
The weather wasn't great. I like proper sunshine on holiday - and mid August I had to wear my rain coat a few times. also managed to sunbathe and swim outdoors, so it wasn't all bad!
The second time we tried a park we flew to Spain and stayed with Thomson Al Fresco at Vilanova Park. This was huge - and very busy. Kind of enjoyed it, but I would say that was for older children. I didn't see much on offer for young children - or in fact much organised activity at all.
So Brittany - risky weather, but beautiful scenery. A little further South to the Vendee i think the weather will be better. My favourite recent visit is to the Charente Maritime. We have just returned from a place near to La Rochelle. Lovely place - and the weather was glorious. There are lots of places to stay there- it is very touristy.
How far do you have to travel in the UK? Try not to do too much drivin at once - it is easy to underestimate the distances and how tiring it is. That would be my tip.
One year we went all the way down to the Llanguedoc region - I made sure that we took our time with that one - stopping off for two nights in different towns en route.