Moving Steam stuff can be rather "long-winded" to say the least. If you have a 2nd usable hard drive, you just create a 2nd Steam Library on the 2nd hard drive, and install the game to that. If however, you only have one usable hard drive, such as a laptop usually, then you are left with re-installing Steam itself, as well as your games, or "moving" things manually, which basically accomplishes the same thing. Consult "
Moving a Steam Installation and Games" on the Steam Support site for some info on that. You can physically copy and move an SH Steam game to another location and mod that, but dependent upon the OS and configuration of the computer, you might have to create a Steam short-cut for it, such that the game starts through the Steam front-end and does its proper "license" check, else the game won't start. When making a copy to move, the original game has to stay where it is installed for the Windows registry to find, and the Steam licensing to use... but no two computers are exactly the same, and ymmv...