We've just come back from two weeks self-catering in Normandy near to Litteau.
We took a car kit for France that can be bought at Halfords and contains all you need legally to drive in France.
We had kids with us from age 11 - 18 and did the following trips, all of which were rated brilliant:
Mont-St-Miohel - it's heaving whenever you arrive but worth it
Villedieu-les-Poeles (very near south of St Lo) - lovely little town and we toured the bell foundry.
Coutances - great cathedral and lovely shops for holiday gifts here
Bayeux - the tapestry of course but be there pre-9am (it is worth the early get-up because the queues are appalling otherwise). Also the street markets there
D-Day stuff - we enjoyed the beach at Omaha - Conseuilles-sur-Mer - and visited Pointe du Hoc and the 360 degress cinema at Arromanches, as well as the American, British and German cemeteries (on the coast road, in Bayeux and at La Cambe).
Lisieux - good town with cathedral and also huge modern basilica shrine of St Therese of Liseiux.
Honfleur - superb seaside town, famed for artists and Satie and lots of medieval buildings and a pretty carousel on the front. And lovely gift shops.
We also dropped in on smaller places - Grandcamp-Maisy on the coast is a cute little seaside village with candyfloss; Noron la Poterie en route to Bayeux has lots of pottery shops.
We also visited Champrepus Zoo - not far from St Lo - very good.
Though this was with mostly teens in tow, they loved it all, and we had done exactly the same holiday more or less fifteen years ago when we just had two toddlers - it's good for all ages.
re the hi-vis vests - the AA site says only the driver is required to have one, though they do like it if the principal passenger also has one.