I’d assume it involves a lot of reversing.
here’s how I see it:
Corona to 207
Queensboro - transfer to Astoria line
57th/7ave - transfer to the uptown Q tracks
Lex/63rd - transfer to the F tracks, switch over in the tunnel, head back downtown
47/50 - transfer for the B or D tracks uptown
145/135 junction - get on the goddamn A and haul ass