The original idea came from seeing the name "Barkley, Shut Up and Jam" and thinking putting "Gaiden" at the end would sound really cool. He's never actually played the game.
Exactly two Pump Rants weren't written by him. One was by a guy who played the demo and thought the rants were serious. The other was written by a friend of his who took almost all of it from a post on SA. (Boyardee did not know of SA at the time).
The idea of the rants being from Truck Pumps came from one of the other programmers having once gone by the name of "Turkpimp". A running gag in some games they made involved him, and over time it devolved into "Truck Pump".
The poem sidequest stemmed from an experience where a rather wretched girl cried after being told by Chef Boyardee that he wouldn't take her to the prom.
The idea of Zalatar the turkey came from a fake story he posted on a Furry Fandom website about having been a punchbag for bullies and finding his true calling by being the Turkey in a thanksgiving day parade.