To be honest, I don't know if the Steam or GOG versions use the DOS version, but I suspect that isn't the case.
Gog's doesn't; I doubt Steam works with any DOS exe ~and would likely not include it.
I found an old CD copy of Fallout 1 lying around (inside a dual-jewel case for Fallout Tactics) and I downloaded DOSbox, but I don't know how to get it to work. Can someone help me with this?
Install Dosbox (0.74)... I'm not really current with MAC & Dosbox, but in theory, you make a Fallout Folder in "Applications" and read the Dosbox documentation for how to mount a folder as a drive. You can add those commands to the end of the Dosbox.conf file; (hopefully that's the same name for the file on MACs). This would let you run Dosbox and have it load with the Fallout folder mounted as the C:\ drive; and (later) you could then type "Fallout" (or also add that to the end of Dosbox.conf) to run the game.
First Dosbox needs to be setup, and fallout Needs to be setup. For Dosbox Edit the Dosbox.conf file, and set the ram to 32MB (the file is well commented, and explains how to do this)... that might actually be all you have to make sure of for Dosbox. For Fallout though; I doubt that the installer will work for you, but it might. You could try running Dosbox, mounting the CD (using the 'Mount' Command and the Dosbox built in help), and switch to the CD drive (still in dosbox), and run the installer ~choose C: to install to, and do the full (
Humongous) install. If it works, then Fallout will set itself up automatically ~if it does not, there is a tutorial for installing Fallout on to Windows 2k that (conceptually) has all the information you'd need to install it manually (into the Fallout folder you create in the Applications folder).
http://www.nma-fallout.com/article.php?id=1593
Ultimately, I'm sure you can put an alias on the desktop or Dock that loads Dosbox, and with the Dosbox.conf set to auto-mount the folder, and auto-run the game.
Then the game would run with a single click.
*(Add Exit as the last command in Dosbox.conf, and Dosbox should auto-quit when you quit Fallout.)