Kevin,
If you are travelling via the Caen Ferry (Ouistreham), then there is a good municipal camp site at the edge of the town - at the junction of the D84 and D514 - entrance off a 5 way roundabout.
An easy 15 minute walk into the bright lights of Ouistreham and about 12 km to Caen itself.
However, if you are driving past Caen from one of the other ferry ports, then maybe somewhere like the two Castel camping sites close to Lisieux would be better? We've stayed at both (different years) for a few days to enjoy Normandie before heading off further South.
www.les-castels.com
Camp-site "Le Brevedent" and Chateau-Camping Le Colombier" - both are good and located between the N13 and the A13, and about 20 km before Caen.
Robert