Metropolitan Avenue, Middle Village, Queens
The Circumferential Line north of the Fresh Pond Yard would use the New York Connecting Railroad line, which proceeds through Middle Village in a trench.
The BMT Myrtle Avenue Line (M train) terminates at the Metropolitan Avenue Station. The NYC Connecting Railroad freight track runs just a few feet east of the BMT tracks, so building platforms and a transfer path should not be difficult.
The NYC Connecting Railroad then proceeds through a short tunnel under Metropolitan Avenue and a portion of Lutheran Cemetery before emerging in a trench.

Metropolitan Avenue station (M train)

Tracks running under Metropolitan Avenue

Tracks run under Lutheran Cemetery

Tracks run under Lutheran Cemetery

Middle Village

Middle Village - Queens Crap

Middle Village - Frank T. Lang Building

Middle Village - Pariscien Cafe

Dos Tacos

Half a million for a tiny old house in Middle Village

Archie Bunker's house (from the opening credits) in Middle Village

Tracks emerge from tunnel under Lutheran Cemetery

Tracks running through Lutheran Cemetery

69th Street passing over tracks

Tracks running under 69th Place

69th Place bridge over tracks

Tracks just past 69th Place

Multifamily brick homes - Juniper Blvd. at 69th Place

Brennan Field - Juniper Valley Park

Brennan Field - Juniper Valley Park

Lutheran Avenue between Juniper Valley Park and the tracks to the west

Breach in track fence along Lutheran Avenue