Zork's (and text adventure games in general) maps aren't grid-based, so you don't need graph paper.
The better way to map Zork is to treat it like a non-planar graph and use graph paper to build an adjacency matrix [1]. Since Z-machine is a bytecode VM that often ran on 8-bit computers it's a pretty safe assumption that the game likely has 256 or fewer vertices in the graph. So if you give every area you visit a 2-digit hex ID you can make the matrix small enough to be manageable.