Hotel reservations needed for L visa

To obtain an L, in addition to a round trip airline ticket, do I need hotel reservations for the full trip, or is a reservation for part of the trip acceptable? My plan is to spend a week or so in Nanjing, for which I will reserve a hotel room in advance, and then move on by rail to Shanghai. I would prefer to have some flexibility about the date I travel to Shanghai, and would prefer to reserve a hotel there after my arrival in China if this is possible. Any advice welcomed.