Nellan is Thirsty Trivia (Commodore 64)
This game was originally distributed as type-in code under the article name "Write Your Own Computer Fantasy Simulation" (or CFS) in the July/August 1980 issue of Recreational Computing (along with The Wizard's Castle, incidentally). This one program would work for the Tandy Radio Shack Model I's Level II BASIC as well as the Zenith / Heath flavor: having the map display appropriately depending on which microcomputer it was running on was accomplished by REMarking out the lines containing graphics instructions for the other computer.
Dr. Furman released a second CFS -- a sequel of sorts, based on the same codebase -- entitled CAKE (or Deliver the Cake), published in Recreational Computing one year later. Dr. Furman recounts: "It took my daughter's fourth grade class about twenty minutes to solve this CFS."