Yup i done this a few times!...and before anyone mentions it,..one time it didnt end to well!!....However,...id ride down personally,..ferries to spain make it easy, the ride from santander to the south is easy and scenic. There are now not that many tolls which are avoidable anyway. The roads are generally fine,..though watch some local spanish drivers!..roads can be slippy as fuck,...Stop signs mean nothing to spaniards! Apart from that,..enjoy it,..good scenic routes,..food is generally shite,.but thats me!...off the beaten track you will no translated menus,..so unless you speak spanish its a shot in the dark,..DONT argue you spanish cops (they get right shitty)....and if it does go wrong,..spanish hospitals are good!!