Hi blacksmithy,
Funnily enough that book mentions one of my relatives too, Robert Tannahill, the Paisley Poet!
Though I am not a Habbie (born and bred in Kilbarchan), it sounds as if Town Foot must have been down near the entrance to Glentyan Estate at the bottom of Church Street. At present, that is where the road splits to go towards Lochwinnoch to the right and Howwod to the left. You can actually see, though not particularly well, this junction on the current Scotrail advert called "Roll with Us" being shown on TV at the moment and also on the usual site to look for videos. The first 19 seconds are all Kilbarchan but this particular area is at about 9-13 seconds.
Regards,
carolineasb