Easy peasy. Simply go via Maldon:
A127 to A130, as usual.
At Rettendon Turnpike, take the A132 towards South Woodham Ferrars.
(If you don't like the A127 and A130 you can also go through Rayleigh and Rawreth to get to Rettendon Turnpike. I've driven that route several times but it's a bit tricky to describe! Look at a map if you're interested in it).
At South Woodham Ferrars keep straight on (B1012) towards Burnham on Crouch.
After about 4 miles, go left onto the B1018, towards Maldon.
Keep following the B1018 until reaching the A414, which is the Maldon bypass. Turn right onto the bypass. Follow the signs towards Heybridge and the B1022.
Follow the B1022, through Tiptree, into Colchester.
Chris