advanced bookings required for Visa application?

Hi, we are two Dutch travels who plan to take the Trans-Mongolian Express train to Beijing. We are planning to travel through China for 3 weeks and cross the border (overland) to Laos. To apply for a tourist L for 30 days, are we required to book our busticket to cross the border to Laos in advance? Also, do we need to plan all our hotel reservations in advance in order for us to get the visa? Many thanks