I downloaded the original PDP-10 Fortran source last night. I've begun porting it to integer BASIC. Hopefully it won't be too large of a file.
Has anyone thought of porting Dungeon (The mainframe version of Zork). The Fortran source and multiple other sources can be found at http://www.wurb.com/if/game/2
I'd stick with the dungeon-2.5.6.tar.gz, It's the earliest I could find. The later the version, the more stuff people add that's wasn't originally in the game.