Duct configuration, duct size can improve your circulation and deter it also. Make sure they are properly wrapped and bends are to a minimum.
Consider this experiment, try blowing through a straw and blowing through a 1 inch dia tube. Same principal with ducts. I would want a big duct going to that back room for sure. But not too big to rob the other more livable rooms. Its a compromise and only pros know how to arrange it.