I breadboarded the LFO, partly to verify it and partly to figure out which way around I wanted the LED. Seems to work, though it looks like the triangle wave gets untriangular at the high frequency end. No big deal. I’ll go ahead and solder this up soon.
In case anyone wonders, I get frequency ranges of 0.014 to 2.5 Hz in the LOW switch position and 1.4 to 250 Hz in the HIGH position.