You'll probably have to make a .bat file (I think) or add in a comment at the end of your dosbox.conf file [autoexec] and mount your game as a virtual CD.

Something along the lines of this:
mount d e:\ -t cdrom
mount d c:\dosgames\fallout -t cdrom

This is a wasted effort on your behalf trying to run this though...

It's going to run so chunky that it will feel like you're playing Fallout, the board game. *lol*

Good luck!