Ok - so, working on the 'Shorter Route' as the basis (roads not yet locked in, just the general 'route') my thoughts are...
Overnight ferry from Portsmouth to Cherbourg.
Day 1 - as we have done the Brittany/Normandy region fairly well, I suggest a 'faster' blatt (not too small roads) to the first stop point.
For the first stop point I suggest 2 nights at the fantastic small hotel/B&B a few of us stayed at on 'The Long Way Up'. Hotel La Vieille Maison.
(A request from TeaBag!)
Mileage would be about 360 miles... so quite some way - hence the use of 'larger' roads' for the first part through Brittany/Normandy.
Day 2 - spent exploring the local region, such as Parc Naturel Regional Pengord Limousin?
Day 3 - blatt over to Parc National des Cévennes, for another two night stopover. About 300 miles.
(But there are some great roads and locations around Bergerac, so may want to split this?)
Day 4 - explore area around Parc National des Cévennes
(There are some really great roads and locations here!!!)
Day 5 - head up to Parc Naturel Regional du Morvan, for a one night stopover. About 300 miles, depending...(Those that want could make this a 2 night stopover to extend the trip further, or could head to Provence on day 5 for a stopover there - somewhere around 'Seillans' for example? Lovely little town...)
Day 6 - head to Park Naturel Regional du Perche for a one night stopover. About 225 miles.
(We have driven through some of this area on the way back from Le Mans, but...)
Or, head to Park Naturel Regional de la Haute Vallee de Chevreuse? a bit closer to Paris (close to Versailles... but I am NOT doing those queues again!)
Day 7 - head to Le Havre for the evening Vomit Comet home... about 115 miles...
The concern is that averaging around 300 mile on day-3 and day- 5 could be pushing it?
If the trip could be extended to 10 days we could do more/make the travel days shorter distances???