planning a superfunexciting easter trip through the north of spain and portugal, currenty planned route: santiago de compostela -> vigo -> porto -> coimbra -> lisbon

between santiago and lisbon we have 9 days which are open to revision. are there other cool places we should incorporate? i'm most excited for lisbon and porto obv but are any of the others worth spending more than a day/night in? is there much to do in santiago de compostela other than look at churches and pilgrims? i hear portugal has some of the world's best hostels, have you been to any of them? is the food and drink as awesome and cheap as i keep hearing? what will the weather be like in march/april? help me maintain my excited travelplanning mode!!!