London underground help info

Can anybody help me out on traveling to Upton Pk via the underground.

I'm hoping to get to a few home matches this season when it's my Saturday day off ( Sundays will be better for me).
Where I use to park off the barking road it's 2 hr parking, last time I went with a couple of mates ( there first time 2 seasons back ) I parked at the back of the Town hall in Basil Ave near the central park, but it was a pain to get back on the barking road for the M11 via the north circular.
One of my customers who used to live at Dartford told me to try the tube from Upminster to Upton pk but looking at the engineering works that goes on at the w/e it only goes part way...any help or advice would be appreciated ...also I know were a few weeks away for the start.