You' ve got your work cut out for you. Once the scalp fully dries hard...man is it tough to get off. It can be done, but it' s not much fun. You might just think about mounting it on a plaque as is.
As far as mounting it goes, if you get a skull mount kit, they usually have some sort of hardware with it. If you decide just to hang it up, or put it on a plaque as is, just drill a hole (or 2) and screw it on.