> Excellent, I've been trying to figure this out; whether I will be able to just jump on/off using my debit (or Oyster) card as I currently do on the over/underground.

Note that you can also use contactless or Oyster on National Rail within the zones, e.g. King's Cross to Alexandra Palace or Moorgate to Finsbury Park.

> Any idea how far out of town this ticketing system will be usable? Will someone in Reading be able to use a contactless card without having to buy a paper ticket?

At the moment no. One would hope that common sense will prevail.