Cherbourg to Camposol

https://goo.gl/maps/DTougxCSNCVPPBSy9

Nantes, Niort, Bordeaux (plenty hotels to stay around the city).

From Bordeaux you have three choices - Bayonne, Pau and Toulouse. Toulouse route adds around extra 200km, it's lesser mountains but way busier around Barcelona.

My favourite is Pau route but it slow and mountainous although it's no tols after Pau towards Zaragoza.

Depending on your crossing time, your driving habits etc. you need to plan your journey for the rest stops. It will be no issues to find convenient hotel on your route in France right up to the Spanish boarder. In Spain they are exist, hotels suitable for the travel, but seems that you need to know somehow where they're are.

Done it many times. Rouen, Drexel ,Chartres , Blois  A20 towards Toulouse mainly toll free. Check out La Flambé b&b near Blond - the best. After Toulouse on to Ax les Thermes , Andorra overnight for us, then down toward Valencia toll free from there. Good luck Malcolm 

You're not going to Rouen or Chartres from Cherbourg.

 Via Toulouse from Cherbourg is a longer way, well, Andora route kinda cuts the corner but not everyone's cup of tea to drive those serpentine roads and that silly toll tunnel, although it's very picturesque route.

A23 in Spain for me much quieter and shorter way especially after road works finished near Huesca.

My route is minimal tolls as I hate paying them. Andorra is perfectly safe to drive never had a problem and we never go through the tunnel . More picturesque over the pass. Perhaps I’m a more of a risk driver. Stayed in hotel Bruxxels in Soldeu fantastic. Easy drive down south from there.