We rated the Minho region as great for cycling, with enough traffic-free roads to allow planning of a safe cycle route anywhere, given time, and good bus services to allow folding cyclists to make rapid dashes between towns when necessary. Although the roads are hilly, the slopes were hardly ever worse than the 15% which represents the point where we have to get off and push.
The costs were reasonable - our double rooms cost 35 to 45 euros, and dinner complete about 30 to 40 euros. We got by without speaking any Portuguese, although being able to speak French was a great help.
If you don't happen to have a yacht in the area, there are cheap flights to Santiago de Compostela in Spain and Porto in Portugal, with easy train and bus connections to the larger towns in and surrounding the region.