No need for a route description.
Starting from Elvet Bridge (the Park and Ride bus drops you off close to the bridge), walk up Saddler Street towards the Cathedral.
After visiting the Cathedral, exit the Cathedral via the Cloisters.
Turn right in College Square and in a building ahead of you there is an tunnel entrance to a passage way.
This passage way leads to a path down to Prebends Bridge.
Cross the bridge, then turn right to follow the footpath beside the River Wear.
Exit at Framwellgate Bridge then turn right up Silver Street to the Market Square.
From here return to Elvet Bridge.