I have put a question on RSVP to ask what attraction you would like to visit.
Many ways to get to York. Train tickets are £12.30 return. Suggested trains: Leeds 09:28 to York 09:51 and York 18:12 Leeds 18:37. Please note these are off-peak return tickets. They do not need to be booked ahead of time to guarantee the price. It also means that should some participants decide to stay in York longer that evening, their tickets will be valid for other trains on the day.
It is possible to drive to York of course but parking close to the city centre can be a nightmare and is expensive.