This episode was directed by Terry McDonough, who directed 3 episodes on Breaking Bad (2008). One of them is Better Call Saul (2009), the episode that introduces us to Saul Goodman (Bob Odenkirk).
It is heavily possible that the graffiti mark left in front of Jimmy (Bob Odenkirk) as he uses Nacho (Michael Mando)'s contact number on the phone booth might be from Jesse Pinkman (Aaron Paul). This is not only because it has the word "JP" on it, but during the teaser in the Breaking Bad (2008) episode Problem Dog (2011), the exact same mark of graffiti is shown behind Jesse.
Nacho's phone number, 505-242-6087, actually goes to Nacho's voicemail if you call it in real life.
Mike (Jonathan Banks) references The Pine Barrens, while telling Saul (Bob Odenkirk) about places people might go to be whacked. The Pine Barrens is an actual New Jersey location infamous in organized crime for being a body-disposal area. In an episode of The Sopranos (1999), Paulie and Christopher take a Russian mafia member there to bury.
When Jimmy (Bob Odenkirk) enters the room with Chuck (Michael McKean) at the beginning of the episode, he quotes Johnny Carson's "Here's Johnny" intro. At the end of the episode, he quotes "Here's Johnny" once again when he enters the Kettlemans' tent, but this time being a clear reference to the movie The Shining (1980).