Around 13 miles.
According to maps.google.co.uk, it is 286 miles by road from Wickford to Plymouth.
20 miles taking this route:Take A127 LONDON, from Wickford, to A12 to ILFORD and CENTRAL LONDON at GALLOWS CORNERS.Take A12 to A1112 DAGENHAM at MOBY DICK.Take A1112 to A1240 (Heathway) DAGENHAM, via Wood Lane.Take A1240 (Heathway) into Dagenham.
For exact driving distances it is best to use one of many internet sites which calculate routes.See the Related Question.
37.1 mi (about 1 hour 9 mins) per Google Maps
Yes . It adjoins London on its northeast boundary.
Chelmsford to Stoke is 182 miles about 3.5 hours to drive
30 miles
Sunderland to Essex is 290.22 miles
miles between Wimbledon and London
Braintree to Chester, 215 miles Braintree to Essex, 220 miles Chester to Essex, 90 miles
It is 102.33 miles according to MapQuest.
Essex County in England covers an area of approximately 1,417 square miles.