I couldn’t figure out how to view the hidden user library folder on Mountain Lion, part of the reason why is because there is a space in the name of my external hard drive. Having a space in the name is ok, here’s how I finally got it to work.
Type chflags nohidden
(Leave a space after nohidden)
Drag the user directory from Finder to your terminal window.
Add /Library to the end of the folder structure.
chflags nohidden /Volumes/DRIVENAME/Users/YOURNAME/Library