How can I use aliases in the Go to Folder dialog?
There's no nice way to set up an alias in the Finder like you can in the Terminal, but you can set up text-expansion abbreviations in the Keyboard System Prefs' Text tab.

I prefer Typinator myself, as it is much more flexible and full-featured than the system prefs.

You could also roll-your-own utility using a script-runner utility and Applescript.