Imagica1975 writes:
... do you HAVE to make a reservation to find a place to stay?
It's always advisable to have a place reserved in advance, if only because you should have gotten a price with your reservation and as a 'walk in' you are pretty much at the mercy of the Desk Clerk. Hotels publish their Maximum room rate and that's probably what you will have to pay with no advance reservation.
... I get the impression here that in Spain, reservations are a requirement and "walk ups" would not be accepted.
Not so! If a Hotel or Hostal has a room available they will probably rent it to you.
... I would like to keep my trip to Spain somewhat open-ended. Ideally, I just want to buy the unlimited travel E-Rail pass for 8 or 10 days and just bounce around Spain.
In off-season I have had pretty good luck with people who wait at Bus or Train stations and ask if I am looking for a Pension. Don't plan to arrive after 9:00 PM and expect to find lodging without a reservation.
In two places, I had a reservation and arrived a day early and both places accomodated me (Hotel America in Vigo (Pontevedra) and Hotel Santa Maria in el Puerto de Santa Maria (Cadiz)).
BTW
You may save a few bucks (or Euros) if you but a Spain flexipass rather than a EurailPass.