Hi banni - I've done this leg of the Clyde Coastal Path a few times - usually cycling (it's a nice loop with the Erskine Bridge at one end, and either the Renfrew ferry or Millenium Bridge at the other).
There is an official website for the Clyde Coastal Path, but sadly the route pages seem to have stopped working:
http://www.focrt.org/ccp/From memory the official route takes you straight along the road into Inchinnan. To continue to Erskine Bridge, you take a right turn onto Park Road, continue on to a footpath, then on to Newshot Drive. Follow this until you reach the paths at Newshot Island. I can't remember the official route from there, but I think it heads inland too early for my liking anyway - much nicer to keep to the coast and explore the beach at Boden Boo.
MrsOrr wrote:It is possible, I believe to walk from that car park around to Erskine ... This road leads to the Erskine sewage works and just before this there is a track/road off to the left and this, I believe takes you into Erskine.
I've never tried MrsOrr's route - but if it's doable it would definitely be nicer on foot than the main road.
Anyway - attached GPX is the route as we tend to do it. Obviously, you can stick to the path under the Erskine Bridge if you want to continue West past Mar Hall. Hope that helps!