Hi Susan.
It sounds like a very nice trip. You will get to see an excellent example of the areas of Cuba least touched by tourism.
On this website, we do not have all of our casas posted. My assistants in Havana can certainly help you book a casa in Santa Clara, Camaguey and Holguin. I am not sure if we have good contacts for casas in Bayamo, Santiago or Baracoa.
I would suggest that you contact my assistants in Havana at the following email casas.bestcubaguide@gmail.com
For other casas you should check out the following website. I have found it to have very reasonable prices and the service was good. http://www.bbinnvinales.com/bedandbreakfastrentweb/
Also, note that for many of the places in the far east of Cuba, you are best off simply finding a casa by walking around the town. Tourism in these areas is low and vacancies for casas is high. You can always find some good deals just by walking around for a few minutes and asking around for a casa. Honestly, that is the way I usually find my casas.
take care,
Mario