Under construction – both the page and the route!
There is a gap in provision for cyclists between Conisbrough and Rotherham. Hopefully the Sheffield City Region plans will sort that out. You can get quite a lot of the way alongside the South Yorkshire Navigation (go through the housing estate on the east side of Swinton station) but you have to go up into Rawmarsh and back down again to get past the Aldwarke steelworks, then there’s a thoroughly nasty bit on Aldwarke Rd (pavement recommended) before you can bump your way into Rotherham along the towpath.
At Rotherham Station you join NCN6 for a good quality and well-signed route along the Navigation, switching to the Five Weirs Walk at Meadowhall.