Dark Forces runs on DosBox .70 like a dream.
Have two mounts, one to the DF folder, one to the DF cd.
Make sure to run the setup in DosBox first(imuse.exe), use Sound Blaster and it's default settings, if you want better music, goto advanced and choose General Midi for the Music.
Basic Settings for Dosbox to run DF smoothly. Anything else is to to your taste.
--Dos Memory - 63MB
--Cycles - 20000
--CPU Core - dynamic