Santilina del mar is very scenic, and has an awesome bar in the main square with a big BBQ in it. Go for the ribs and chorizo.
Hotel del Oso is a nice friendly hotel near the cable car in mountains. Potes is a nice town with good eating in it. The roads are awesome, real gs country.
On a slightly more helpful note - there's a ton of advice in this section. If you're going in early Oct there's a rally in Colombres [not the Moto Pistons in Santander] that should be worth a look.