We have been using Hotel.com and Airbnb.com. Is there another site that is preferred in Spain?
For small charming hotels try hotelesconencanto.co more countryside accommodations try CasasRurales.net or EscapadaRural.com
My Spanish friend, who lives in Spain, tipped me off to these kinds of searches several years ago. I also use booking and tripadvisor in my initial searches for places to stay. I use these bigger search engine sites to find properties I want to consider but then I always email and book directly with the property. The only time I can't do this is when I find a place on airbnb that I cannot find elsewhere.
For beautiful historic places converted into hotels look at paradores.es
Thanks for the input! We will put them to good use.
If you're at all interested in historic hotels; converted from castles and other amazing old buildings, you can sign up as a member of paradores.es. These places are pretty phenomenal and they often have amazing dining since they are required to offer local food.