Ok, here's the script file...
-cdgpurge
p
-psetupin
;enter your default drawing location including drawing name here
;enter your page setup name here (one word pagesetup names work best)
This one is using the CDG Purge for deleting all previous pagesetups, but you can use an existing lisp you have or not include that protion of the script by deleting the first 2 lines of text from the script file.