Once the route crosses the Black Cart Water at Johnstone we picked up Route 75 to Gourock following the disused railway past Bridge of Weir and Kilmalcolm. At Port Glasgow there was too much broken glass to be able to use the cyclepath so we dropped down into Greenock and made our way through Battery Park to Gourock.
The original plan was to catch the ferry from Gourock to either Kilcreggan or Helensburgh, but we discovered that neither of these services run on a Sunday, so we hunkered down in a cafe on the seafront to decide what to do next.
Eventually we headed on and made our way around the coast as far as Inverkip, and had several false attempts before finding the correct road up the hill for Loch Thom. We saw the interesting features of the Greenock Cut and Kelly Cut before reaching the Cornalees car park beside Loch Thom. The next section was along rough forestry track past the Gryfe Reservoirs, before dropping down the hill and re-joining the cycle path back into Kilmalcolm, where we stopped briefly for Frijj milkshakes.
The next target was Bishopton, but we kept taking the wrong roads, so ended up doing a massive zigzag to finally reach the approach road to the Erskine Bridge. I've only lived in Glasgow for 20 years, and this was my first cycle over this impressive bridge, with an exciting steep descent towards Old Kilpatrick. From here we had a straightforward return journey along the Forth and Clyde canal towpath.
Total distance = 127 km or 79 miles.