Is it possible to get a program to select a file just plotted and have it
sent to a backup folder ?

And the answer is :

Copy and paste this coding into Notepad and save it as "EndPlot.lsp". You must only load this application. "Do not run it, as it contains reactors".
Open the drawing you want to plot, and then load the application : (load "endplot")
Plot your drawing. At the end of the plot the application will first Save the drawing to the current directory, and then SaveAs, to a directory called "c:/backup/". You can quite easily change the directory path to suit your backup directory.

;CODING STARTS HERE

(prompt " \nLoad Only....Do NOT Run...")

(vl-load-com)

;*******************************************************
(vlr-command-reactor

nil '((:vlr-commandEnded . endPlot)))

;*******************************************************
(defun endPlot (calling-reactor endcommandInfo /

thecommandend drgName newname)

(setq thecommandend (nth 0 endcommandInfo))

(if (= thecommandend "PLOT")

(progn

(setq acadDocument (vla-get-activedocument
(vlax-get-acad-object)))

(setq drgName (vla-get-name acadDocument))

(setq newname (strcat "c:\\backup\\" drgName))

(vla-save acadDocument)

(vla-saveas acadDocument newname)

);progn

);if

(princ)

);defun

;*********************************************************

(princ)

;CODING ENDS HERE