Frankie DePalma's parents are mentioned to be Joseph and Helen. These are the names of Tony Shalhoub's parents.
Monk says "I just wanna put this kid 10 feet under," to which Lenny Barlowe (played by Eric Balfour) replies "6 feet under." Eric Balfour was in the show Six Feet Under (2001).
When Monk initially enters Frank Depalma's room, he is describing the room and his actions in great detail. When he gets to the bar with the large LCD TV above it, he describes the bar and its contents and says "...some type of blackboard... no chalk." This appears to be an allusion to Mr. Monk and the Really, Really Dead Guy (2007), where he writes on the "blackboard" in the federal agent's van, which turns out to actually be a TV, much to his surprise.
The opening scene appears to be an homage to the 2008 film Ghost Town (2008) where the identical incident happens to Greg Kinnear's character near the beginning of that film as well.
This is the fourth time since Trudy's death that Monk has worn a tie. The first time was in Mr. Monk Meets the Godfather (2004), although that was because the tie was a wire. He wore a tie in Mr. Monk Goes to the Office (2005), and in Mr. Monk Is at Your Service (2007), he wore a tie as part of his butler attire.