We have used the B1002 lots of times outbound in the morning as an ECE route, but only once or twice inbound as we had a much nicer second leg going across to Harlow and picking up a London train from there. Watch out for Chelmsford, our avoidance route both ways was Galleywood, Great Baddow, Boreham having tried the return along the main road once at end of shopping time (never again)