You can take the main rd from whittlesea to the top (Kinglake West) which is a steeper climb than humevale rd, but you can get rests as it flattens in sections wheras the humevale rd climb does not give you a break till you reach the top.
There is a bunch ride from the bundoora hotel at 7:30am on sat and sun (I think) that goes there.
Tomorrow i'm going from Heidelberg to Wallan and back via Whittlesea, another good ride quite undulating although it has a narrow shoulder after whittlesea.