A shorter version of the Waterlink route, return via Southwark low traffic streets. Some of the best bits of the Waterlink Way (Cator Park, River Pool Linear Park, Ladywell Fields), but a manageable 12-13 miles with lots of parks and a few hills, suitable for confident riders age 8+.
Highly recommend a stop for lunch or a pint or three at the Ivy House pub on Stuart Road (great pizzas & easy cycle parking). On the way back there's the café at Dulwich Park, the Greyhound pub or Au Ciel on Dulwich Square to top up blood sugar levels before the big College Road hill climb.