<i>this is not full access to the comp, only to terminal.</i>
Not actually the case either. At the prompt, type
open -a <application>
where <application> is the name of whatever app you want to run. Whoever you were in that terminal, that's who the app runs as. So, su root, and then open -a TextEdit (I don't know if capitalization matters). Now you can edit config files owned by root, in a graphical editor.
I believe that the app has to be in the /Applications directory for open to find them