Hi Derek, I would recommend just using /d for all directory links unless you have a need otherwise.
A word of warning for your task of relocating the Windows User folder, you will encounter problems. As the C:\User folder is classed as a critical directory. It is protected by Windows and your symlink to the D: drive will be replaced with a new C:\User directory after your next reboot.
As a work around you can manually move the sub-directories within a C:\User\[user name] directory. Using Windows (file) Explorer if you right click on C:\User\Derek\Downloads, select the Properties option and then select the Location tab in the Downloads Properties dialogue. From there you can move the location of your downloads to a new drive or directory. It only works for Windows created public sub-directories such as Music, Pictures, Videos, Save Games etc, so it is far from a perfect solution.
Otherwise if you’re brave you could try following these instructions.
http://lifehacker.com/5467758/move-the-users-directory-in-windows-7