Here's a start for Spain heading from Santander down to the med coast which took a couple of days (the colour beside the route bit etc describes the background style of the route number used on the map I have. {I hope} red is A road & above, green is B road & below)
623 between Torrelavega and the Reinosa junction.
111 between Logrono & Soria.
211 from Caminreal (south of Zaragoza) towards Montalban then the 420 to Teruel.
226 from Teruel east to Vilafranca del Maestrat.
152 from Ripoll north into France at Bourg-Madame, still heading north on the N20 to the Col de Puymorens (not the tunnel!) into Andorra, do the passes not the tunnels
260 west from Adrall (near Spain Andorra border) as far west as you want - Jaca will take you at least 1 day, but boy is it good.
We did these routes fully loaded heading from one campsite to the next and didn't have much time to go exploring off the main route we'd chosen - maybe next time.
