Re: Spain in late April
 

Hello Ed
I live in half-way from Santander to San Vicente de La Barquera (Mazcuerras, closer to San Vicente, actually) so I usually ride most of the roads you're planning to ride on your first day in my country. The road between Cabuerniga and Reinosa is twisty and nice, but there are many trees and springs on it's first half, so you must expect tight corners in the shade and wet tarmac. It would take more time, but I still think it would be some kind of a pity if you miss the road from Puentenansa to La Hermida (plenty of twisties and amazing views, plus less wet corners). You can get to Puentenansa from San Vicente (nice road as well, but way more faster and prone to have a couple of police cars with speed cameras). You can get to Puentenansa from Sopeña, through "La collada de Carmona" which is quite nice as well. When in secondary mountain-ish roads be aware of cattle and horses, as it can be in the middle of the exit of a corner anytime during springtime and summer
I hope you have a lovely time here. If you want an "almost-local" (been living here for five years now) to join you just write me a line... as long as it's not raining I'm always willing to ride some twisties!