I love this walk, I tend to park at the free car park at The Carrs and walk through the woods to the river then follow it to Manchester Airport. You can either return through Styal itself or retrace back along the river. Easy to find your way back as all the bridges over the river have nameplates with names like "Kingfisher Bridge". For a quick river walk The Carrs itself isn't bad, for this follow the river where you see it from the car park, for the Styal walk follow the path behind the toilets and over the bridge parallel to the road bridge. Car park has toilets but they close fairly early. For satnav/gps users the free car park is at lat/lon 53.33579,-2.24052