Has anybody done this journey recently? Michelin suggests after Chartres, N10 or A20, i.e. via either Tours and Angouleme or Orleans and Limoges, and not much in it in time or cost.
Orleans, Vierzon and Limoges - toll free after Vierzon on A20😁
if time is not a factor, buy some good maps and use the D roads…often very good and you will visit “deepest France”