The name of the episode actually goes back to an unimportant minor character in Douglas Adams' original novel. The dialogue line 'We'll be crushed like Watkin in "Star War(!)" when Todd and Dirk are stuck in the trap with the moving walls is probably just used to avoid licensing hassle.
Hitchhiker's Guide to the Galaxy references: One of the screens in the maze shows the number 42, the answer to the Ultimate Question of Life, The Universe, and Everything.
Todd's concern about the electrical ghost rhino "charging" again is an unintentional pun. Live rhinos are dangerous when they "charge" and so are electrical ones, but for different reasons.