I live in Bonao. I know of one taxi driver named Jhonny, who speaks English. I have not seen him in a couple of weeks, but I will pass by his station tomorrow. I also can find a tour guide for you if Johnny is not around.
My name is Merky. My e-mail address is (Send the OP a PM here on DR1), it is much easier for you to reach me there.
I can have an answer for you before noon.
I hope you enjoy your stay.