Flying to several cities in Spain

My daughter will be attending the University of Barcelona in the spring and my wife and I are going to visit her during holy week. We are trying to decide what arrangements to make to fly there and get around in Spain, too. We will visit Barcelona, Granada, Santander, Bilboa, and Madrid. Iberia's SpainPass appears to be a good deal for flying in Spain domestically, but you must fly to Spain on Iberia to get that deal. We could fly on other airlines and upgrade to business class with points to get to Madrid or Barcelona, but we can't upgrade on Iberia. Does anyone have any experience with the SpainPass or flying from the US to Spain in economy?

I guess you've probable ruled out this possibility but remember that American Airlines and BA miles will buy you an upgrade on Iberia.

When we used an Iberia SpainPass, it wa s 4-segment pass that required a colsed circuit. We flew Madrid-Sevilla, Sevilla-Barcelona, Barcelona-Santiago and Santiago-Madrid. It was a good deal then; but look into what Spanair has to offer. I think they offer a similar SpainPass and all you have to do is fly TransAtlantic on a 'qualifying carrier' (whatever that is). In July I did Madrid-Santander (MotorCoach - 5.5 hrs.) Daytripped Santander-Bilbao; then Santander-Barcelona (MotorCoach - 9 hrs.) and Barcelona-Sevilla (overnight Talgo sleeper) & Sevilla-Madrid (AVE - Train 2.5 hours). Total cost about ESP 40.000 (USD $200)
Air Nostrum (Iberia 'commuter') was the only carrier that served Santander at the time.