Waterloo to Kentish Town (East)

and then follow the bike lane up through Somers Town, Roy Coll Street, right onto Randolph Street, Agar Grove, fork left on to the bike lane Stratford Villas, left Murray Street, right Camden Road, left Sandall Road, right Bart Villas >>> Leighton Road.

+1 on this. York Way is always crammed with buses and construction lorries. The worst you're likely to get going through Somers Town is some school children with knives, and they generally reserve those for each other.