As has been said, France must be about the best country to motorhome in - terrain, climate and attitudes toward you.
You will love France!
Most aspects for your specific "Normandy" needs have been covered by others more knowledgeable than me, so the one piece of advice I'd give for someone who hasn't driven on the Continent before is...
Whenever you drive off, every time, always say to yourself "Keep, right, keep right, keep right", and maybe encourage passengers to remind you too - kids love doing it, telling adults what to do! But it's serious. We've all done it - moved away from a parking place or garage for instance and "reverted to type" by driving along on the left. It's easily done and terrifying when you do it, then suddenly come to the realisation...!!!
The only other part that might momentarily "confuserise" you at first are roundabouts, especially the ones at the Port just as you set foot in France. Just retain the "Keep right" mantra in your head as you approach and go round to your chosen exit. It's only the first few that are problematic. Thereafter you'll be in the swing of it with no problems.
"Keep right, keep right, keep right!"
Barry