Marc, there are lots of sites between, Rouen and Le mans, Bernay, Ses, Gace, and Alecon, to mention just a few, we never book for overnight stays but tend to get to the sites between 3 and 5 pm, so we have time to get to another one just in case!. And I would not recommend overnighting in the service station or Aires. The acsi maps and also the Caravan Club books for Europe give almost all the sites, private and also municiples.
Hutch.