From the London/Essex border, where is the nearest free or inexpensive Park & Ride station with a regular direct connection to Reading?
I imagine that it would be on the far side of the Dartford Crossing, but which? This is a one off, but might become a regular commute, so, depending on the train fair, it might even be better to go nearer to Reading that London? It's a time/cost trade-off, but I don't have any data on which to base the decision.