Steelman,
I sometimes catch the train down to games and find the easiest route is, come out of the station on the Poole Bay side of the station, turn right and walk along to the next right. Sterte Road,you will see the old Poole stadium on your right, carry on down Sterte road and over a railway bridge.
On the other side of the bridge you will come to a three way junction with the ground over to you right.

The others will know more about the pitch than me.
Have a safe journey down.