Also, can anyone tell me, can you book your ticket the whole way at the start of your journey or do you need to purchase tickets at each stop?It depends on the route. It might be possible to buy a "transfer ticket" for the whole journey if you travel along the Keisei-Toei-Keikyu corridor. However, if you use any other route, you will likely have to buy multiple tickets along the way.
would it be better to reserve beforehand?
Trains along the route do not allow seat reservations.