On your shortened holiday route, if you’d gone roughly: Auch, Bergerac, Limoges, Tours it might well have been better.
From the longer holiday route you’d hoped to do (ending a the eastern end of the Pyrenees) we can see that you were determined to hit the western coast / western side of France, irrespective. If you’d have planned on roughly a diagonal line: Perpignan, Limoges, Tours and onwards to the ferry it might well have been interesting.
Something broadly along the lines of this from Kurviger:
ViaMichelin’s suggestion is pretty similar:
Both of those websites are free and very useful to give you an idea of:
i. The direction you need to take
iI. The distances involved
iii. Roads to maybe ride along, which can all be amended to suit your purposes
Irrespective, it’s all down to:
Where you start from, A
Where you need to end up, B
The distance A to B
The maximum / minimum time available to ride A to B
Any other plans you might have for things to see and do between A and B
——
There is a very good Michelin map 726, useful for plotting journeys A to B across a very large country, France. It strips out all the fine detail, leaving just the main roads, nicer smaller roads, the sensible link roads and shows the Bis ‘Tourist routes’, all which will avoid the motorways. Get it.
Are they always ‘Great roads, mate’? No. But eventually, if you want to go A to B, within time period X, you sometimes have to compromise. That’s life.