Columbo meets Milo at the same beach where Jim Rockford lives in The Rockford Files (1974). He walks down to meet him past the restaurant outside Rockford's trailer. Also, Gretchen Corbett, who plays Milo Janus' secretary, played Jim Rockford's lawyer (and sometimes girlfriend).
On the The Tonight Show Starring Johnny Carson (1962) episode Lawrence Welk/David Brenner/Ashley Montagu/Joan Embery (1974), Peter Falk, in Columbo costume, does an unannounced walk-on and describes the plot of this episode that was airing the following Sunday night. It's mentioned he had just come from the Columbo set which explains his outfit.
The tune "This old man" often occurs in the soundtrack, especially when Columbo is thinking hard or when he suddenly perceives an important clue or makes an inference about the murder. He also often hums, or whistles, the same tune. In this episode, he actually sings a few words of the song.
In the hospital waiting room, the painting on the wall behind Lt. Columbo has the signature "Sam Franklin", the same artist from Suitable for Framing (1971) .
Columbo is out of his classic garb for the first time in the series, although only for a few minutes.