So you figured out the CD mount?
My first guess about the choppy music is if you're using an actual CD that you burned your cue/bin to, is this the case? The same problem happened normally back when this game was released. CDs are always very slow. Nowadays you can improve a lot by using the image file or making one out of the CD (you can do so easily with
this free software), put it in your hard drive which is much faster than a CD, and using this image instead of the actual CD to play (in the tutorial, use the imgmount DOSBox command instead of mount).
Otherwise, is your computer (CPU) slow?