Don't know which route you plan on taking but somewhere like Mt St Michele would be a good place if you took the coastal route, then headed south toward Rennes You can park overnight in the carpark there or there is a nice little campsite with swimming pool/bar etc. in the village.
EDIT: Just checked and looks like pool not open - maybe in August
There are lots of campsites and Aires around that area though
Ok for kids and there is always St Malo as a back up.
EDIT: Just checked and looks like pool not open - maybe in August
There are lots of campsites and Aires around that area though
Ok for kids and there is always St Malo as a back up.