What we do at my company is we have a lisp file that we run if we want to reset the variables, all it does is use (setvar) and sets each variable that we may change using a LIsp Program back to what we consider the default.
If you have express tools loaded, then you could use the SYSVDLG command to set a baseline. Have it "SAVE-ALL" to a script file (not the default) and you could run it anytime you need to reset everything. You could groom the script too, if you only wanted to reset certain variables or whatever.
Seems express tools already has a file with all the default settings too.
From Express tools help:
Two files, defaults.svf and defaults.scr, are installed in the Express directory along with the System Variable Editor. These files contain AutoCAD's the default system variable settings for a new installation of AutoCAD. To return AutoCAD to a 'pristine' system variable state you can either read the defaults.svf file into SYSVDLG or run the defaults.scr file from the AutoCAD command line using the SCRIPT command. Be aware that this will overwrite any system variable settings in the drawing you are currently editing.