Where to stay between Calais and les sables d'olonne

[Oohhaveabanana]

Hi, we have 3 (possibly 4) days to fill between Calais and Les Sables d'Olonne. Will have 2 DC's under 13 Like a bit of history, stroll around towns, theme parks etc. Any ideas of where to look would be gratefully received.

I definitely recommend going to Futuroscope and Puy du Fou themeparks while you're at Les Sables d'Olonne.
I'd suggest staying in Caen. From there you have good access to the D-Day landing beaches and Pegasus Bridge. The Juno Beach Centre and Memorial de Caen are both excellent museums. Festyland amusement park is also worth going to.

Domfront is a beautiful historic town to stop and have a look around, stay the night

I think Caen (which is my local town) is a bit off the route. You could go A28 to Rouen and Angers or take a slight detour via the Loire valley and see the chateaux..
Nantes is a lovely town too.

We’ve stayed at Euro camp sites in various things to break up that journey a few tones- safari tent, mobiles, Reg euro tent
If you book a night and the crossings with them it’s usually cheaper too