Dusty - you should find some earlier threads here with pilgrims' experiences and recommendations. To recap on mine from 2012:
Lisbon: I booked the Old Town Hostel and really liked it. Young crowd there, but friendly. Run by father and son. Had a simple but pleasing twin bed room. One bus from the airport to its terminus at the quayside and 10 minute walk (uphill) into the bairro alto. It's about 15 minutes from the church where you can get the credencial (Igreja dos Martires). A leisurely 40 minute walk across town to the castle.
Porto: I stayed at the Poet's which was lovely. It has a range of accommodation options with dormitories on one site and the private rooms in a separate building with sweet little garden about 50 yards away. Communal meal was fab. It's a few yards from the route and about 10 minutes away from the cathedral.
Vilar do Conde: I took the first option in
Brierley's guide, but there are several others listed. Casa de Hospedes "O Manco d'Areia" is just across the bridge on the left and was clean and functional - en suite, no meals. The important thing about VdC is to arrive with enough energy to climb the steep hill above the town to where the Roman aquaduct meets the convent.