Gijon to Burgos best route

[CarbonXKR]

Our Spanish road trip is coming up shortly and although I am familiar with the area along the North East corner of Spain and on into the pyrenees, I've never ventured towards Burgos before and looking for a decent route avoiding the highways and making the most of Picos, gorges, twisties etc.
Here's google maps options, I'm inclined to go with the highlighted route as this takes me along part of the Picos I haven't done and I will have done the North coast route on my way to Gijon (second night after Santander). Should I head East after Gaurdo or carry on South on the highlighted route? Any suggestions most welcome thanks

Edited by CarbonXKR on Saturday 21st April 14:57