On my first platform, the Atari 800, there wasn't even a GOSUB in the ROM BASIC. So the way to do a GOSUB was to set a variable before doing your GOTO to the "subroutine" and at the end of the "subroutine" do a pseudo-return like:
IF rp=1 GOTO 130
IF rp=2 GOTO 780
GOTO 1830
etc.
The code for my bulletin board was a freaking mess. But it actually worked and ran for months between reboots.