An update on my progress aside from any help that comes from here. For King's Quests 4, 5 and 6, I was able to get them to work as follows: copy the CD to the internal hard drive, then run the installer, which goes through fine. However, to run the games, I have to use sierra.exe -- instead of kq6.exe (or 4 or 5) -- which is supposed to be for when you haven't actually installed and are running from the CD. It works, and could be seen as a trivial technicality, but obviously less than ideal.

For Betrayal at Krondor, copying the CD to the internal drive made the installer go through without any errors, but it just doesn't do anything. For that, I found I had to go through Windows XP's DOS prompt (I have a virtual machine run through Parallels). That installed fine, then I just moved the game's folder back into my Mac files and it runs.

Wing Commander 3 tries to start running, but gives me an error it suggests could be caused by a bad CD read.

Any ideas as to what's causing this? Something about the writeability and/or permissions that OS X is giving things is my guess, but I'm not techy enough to go beyond that.