Terry,
In order to get a preview the program will need to backplot the code in some way. Not many free backplotters out there.
For a quick view one could always capture the graphics area after loading and save as a pic with the same name as the code file.
A friend just improved a backplotter he wrote which backplots the gcode directly into ACAD unfortunately it's his to give away
and i can't share it.
RICH