Bonjour from the LeMans sun shine, temp's getting higher about 33 degrees a few minutes ago.
Your site is to the North East of the city . Rob is right, Calais, Rouen and Alencon is the best easy way.
Sat Nav or Via Michelin will even send you that way.
(www.viamichelin.com , set for car and caravan!)
Just remember that Rouen is approached through a huge tunnel and on to dual carriagway around the town. Keep Eyes peeled for the small Le MAns sign right above the road and get into the right hand lane right away as the road loops tightly to right under the road you have been on. The DC road trundles through a large industial area to the "cows" on a roundabout, straight across and the same at next roudabout and loop to right onto motorway keep going past derelict like castle that will be on your right and take signs for Alencon and LeMans of the motorway on E402 which is a left turn.
It is cross country but has good roads and dual carriageways leading to new motorway near Alencon.
Bon Route.
ps. Remember that fuel stations are scarce between LeMans and Rouen in the evening and on Sundays. There is a 24 hour Total just south of Rouen and the 402 at a roundabout to the right!