When I brought Jellybean home in July, he hid a lot at first. It took a long time before I really got the feeling that he was totally comfortable here. Now he boldly goes wherever he pleases!
I don't know if many other people do this, but, I like to make lots of little built-in hiding spots and cubby holes for my cats (I have 3). I like to set up hiding spots for them in my closet, in the children's closets, under the bed, down in the basement, etc. I don't think it encourages them to hide, but, I think it makes them more comfortable knowing that they have many safe little spots to get away from it all. All 3 cats seem to find the spots I make for them, and I think each of them really appreciates the extra efforts. Just a little idea to make your new kitty comfortable at home.
Be patient...he will come around. It takes cats awhile to adjust.
Best of luck to you!