Where conflict seems to occur most is when you have a route which serves both purposes (recreational and commuter) and has high levels of cycle usage. In particular, the Bristol & Bath railway path, the western section of the Kennet & Avon towpath, and the Regent's Canal towpath in London.
Ultimately the only answer here, I think, is to alleviate the pressure by providing more commuter capacity elsewhere - i.e. more safe, direct segregated cycle tracks by roads. As I've written in the pages of Waterways World, London commuter cyclists don't choose the Regent's Canal because they like looking at ducks, they choose it because they don't want to get squashed by a tipper truck.
Of course, neither the Regents Canal nor the K&A have any pedestrian/ cycle segregation. The Regents Canal has plenty of impediments to sustained speed - two on road diversions to avoid tunnels under Edgware Road and Islington, restless natives with their cycle prohibition on the towpath at Maida Vale, plenty of locks, a right hand turn at Regents Park, permanently congested areas such as at Camden Lock and the general disincentive to speed that if you get it wrong you can get wet very quickly and very easily...
I admit I didn't even realise there was much commuter traffic on the K&A into Bath. Presumably it mainly comes from eastern Bath and perhaps Bradford on Avon? It is possible to get up to a fair rate of knots on the towpath at Widcombe flight, but there is a sharp turn there too and a very main road at the bottom, once again I would imagine de-incentivising high speed.
i can fully appreciate why both routes would be a far better alternative than the roads in the area though.
