When Graham first meets the Hobblepots, he asks "So... I just GOTTA know! What is brewing in that cauldron? Is it a transfiguration elixir? Is it an invisibility potion? If I drink it, will I understand the language of creatures? Will I sprout the wings of an eagle? Or a fly?"
The language of creatures and wings of an eagle or a fly are clearly references to King's Quest 3 where Gwydion (prince Alexander) escapes from the wizard Manannan by making these specific potions.
When Graham first meets Amaya in her store and notices the gardening tool (the weed whacker), he asks "So... I've been meaning to ask... What is that amazing blade for? Is it for battling vicious Were-Bears? How many Ice Orcs has it slain? Does it deal justice? Is it road legal? Is it made of fear?"
The Were-Bears is a reference to the Were-Bear in King's Quest 7 and the Ice Orcs is a reference to the Ice Orcs in the Frozen Reaches of King's Quest: Mask of Eternity".
While in the dragon cave, Graham and Achaka crawl through a narrow tunnel which strongly resembles the tunnel King Graham crawled through to escape the Dark Woods in King's Quest 5.
