Emsworth station is a good one. Theres' a free council car park down a the road near the park. 4 min walk, yuo can see the track from it.
https://www.google.co.uk/maps/dir/50.8550143,-0.9404598/50.851499,-0.937917/@50.8520425,-0.9390543,228m/data=!3m1!1e3!4m2!4m1!3e0