Yesterday I was out for want of inspiration up the Don Valley again, and I aimlessly followed other cyclists and found myself heading down-river on the other side. I came to a blocked bridge, and was about to turn back, but the guy next to me said “You can get through”; I was slightly circumspect about rampaging through a construction site - not A construction site, but THIS construction site, as I thought it might be preparatory works for our railway, and it would not help my career to suffer a mishap trespassing on one of our sites. But faith in the Contractor’s safety management, and I followed the other bloke through the gap in the fence. The ground was well-compacted, apart from some material stockpiles there were no obstructions, and no unprotected excavations. There was one “Caution - Drop and Water below” at the edge of the river, and we had to carry our bikes over some material blocking the path, but we were soon out through a similar gap in the fence at the far end. Maybe the path is not legally closed, but the contractor who has access would prefer people don’t use it…
Anyway, it was pleasantly rideable, free of cars, no pedestrians and few cyclists