For me you would struggle to not get bored in the Picos for more than 3 or 4 days as it's not the largest of areas. Some of the roads have been spoilt recently by major road works like Potes to Rianno on the 261 and the road to Fuenta De has a new car park which drags slippery dusty chalky stuff for miles down the road. For 7 days, Pyrenees for me or northern Portugal with a night or 2 in the Picos maybe at the start or end.
