Northern route from Crystal Palace to Balham, using Palace Road LTN in Tulse Hill. Mostly backstreets apart from 50m of Norwood Road. Rosendale is OK on a Sunday - will be much better when Lambeth Healthy Route is finally finished.

Alternatively you can turn off Rosendale sooner on Idmiston Road - but that means a bit more of Norwood Road which is not very nice. I plan these routes to be usable with a kid of 9-10 on Sunday road conditions so I'll trade a longer section of back street to avoid main roads as far as possible.

Using Alleyn Road and the Clive Passage footpath (dismount for that probably) means you avoid the big roundabout at Gipsy Hill - there's a cycle track along the northern side of the roundabout.