What format is the file? aiff, mp3, mp2,
I usually just drag a song/file onto my desktop and open it in an audio editing program, if I want to edit it. If not, I just drag it onto a "New Burn Fodder." That folder will show how much space it is using right on the bottom of a Finder window. A CD holds, what 750+mbs? Should be no problem putting the whole six hours on one CD if it's only 170 total MBs.
However, it is most likely an mp3 file and most older CD players won't recognize them nor play them. Newer models can, of course. And any mp3 player (iPod, etc.) should be able to, also.