If you don’t want a full RD setup, or an IGH, it is possible to run a double chainring to a single cog with a tensioner for chain wrap. I’ve never done this, but I have seen it done.
FD, especially older ones, are generally bullet proof. Once you figure out the GI’s for flats and climbing, just run flat rings with a friction shifter. You can stay in one ring nearly the entire time and only go to the other when necessary.
John