I caught the X19 bus to Ardsley, just three miles east of Barnsley town centre. I took the footpath that goes down by the side of the crematorium and continues down across the fields to the TransPennine Trail.
I went the wrong way because I was concentrating too much on not getting too muddy. I was soon able to join my original route though.
Interestingly, for me anyhow since I like maps, on the online Ordnance Survey map halfway along its route the path is reclassified as a bridleway. I've not noticed this anyway before, I should imagine there are some practical issues for both horseriders and cyclists using the route. When I was there I didn't notice any specific signage. Maybe the reason is an inconsistency as it crosses a parish boundary - I don't know.
I stayed with the TransPennine Trail for four miles until I reached the southern end of Bolton-on-Dearne. At Broomhill the Trail was closed but there was a footpath I could use, although a stretch of this was flooded. Fortunately the water was only a few inches deep and it was tarmac underfoot.