This simple scenario can be used without requiring any expansion of the Sample Dungeon.
The party is sent on a mission to rescue Lemunda the Lovely. The town council, including Lemunda's powerful father, gives them a partial map of the dungeon (including the area marked START on the map in the rulebook), and tells them that "we think the tunnels shown on the map connect with the caves where the pirates are holding her for ransom, please investigate and rescue her if possible". This can be used to introduce new player(s) to the concept of mapping. You can even have the evil Thaumaturgist be a member of the town council (his tower is found in town) and secretly trying to stymie the party.
Furthermore, one of the statues in the Thaumaturgist's laboratory is actually a statue of old Zenopus himself. You see, Thaum used to be his apprentice, until he stole his master's wand of petrification and stoned him. If the players find Thaum's scroll of stone to flesh they can decide if they want to turn Zenopus back to flesh. He will want to reward them greatly but will find he is much poorer since his Tower was destroyed...
Alternately, the statue in Room D can be the petrified Zenopus set on a swiveling base.