Some info from the Shrimpers website:
I would add that if you are driving you can just as easily get to Sarfend on the A13 rather than the A127. You have to join the A127 after the A13 anyway. The A127 gets (marginally) more blocked that the A13 on a Friday afternoon so might be the better option. Also, there is a 50MPH speed camera system in place on the A127 after Basildon, all are working and you can get caught multiple times on 1 stretch.
If you are going my train, Liverpool Street gets you closer to the ground, but you are much more likely to get a decent train ride from Fenchurch, where trains up to 4.30 or so are more quiet. Also, the guards on c2c are more relaxed about drinking on the train I have found. When you get you Southend on the c2c line, the walk to the ground isnt that bad, a few pubs on the way.