Now it becomes more real! Liz, do you have an estimate on your days in Santiago? It would be great fun to meet. I'll bet I'll be later than you, though, right now it looks like about July 12 or 13.
Anemone's recommendation is a good one if you want to stay in a more modern part of the city, near the Corte Ingles is a convenient location for commerce. If you are more inclined to the old part of town, I frequently stay in the Hostal Arcos,
http://www.hostal-arcos.com, run by two very nice hard-working young guys. For a little more of a splurge, the Vetusta can't be beat, though it's not right in the old center.
http://www.hotelvetusta.com (sort of between the old center and the hostal that Anemone recommended). And then the super splurge, the Reconquista.
http://www.eurostarshoteldelareconquista.com/EN/hotel.html I've never stayed there, but I've bought a stay for my son and wife there and it was surprisingly affordable. It's where parts of VickyCristinaBarcelona was filmed and the doorman does his best to keep out tourists. I found that a little offputting, but the staff inside was really quite nice and helpful when I wanted to set up some special things for the honeymoon trip. I love Oviedo, bet you will too. It's great that you will have so much time to poke around. And the sidra street Al mentions is the Gascona.
Buen camino, Laurie