Just a general reflection on pre-booking (and this is simply my opinion):
If you feel uncertain, by all means: Book ahead. BUT:
Many things (can) happen on the Camino:
1. You (may) get blisters, needing a rest day (I needed 4 days once)
2. You find a great village where you REALLY want to stay, before the place you have booked
3. In hostals, you will miss the cameraderie/shared cooking/communal meals (you can only book ahead at private albergues, not the public ones)
4. You may end up in a Camino family you REALLY do not want to leave, gettings new friends for life (I have)
5. You may find the love of your life (it happens) and completely change plans
6. You may want to switch to another route for a few days
7. You are walking according to a set/fixed plan, missing out the spontanious life of the Camino
and likely many more points (please share...)
It is higly unlikely that you will not find a bed for the night. As I have said before: In 7 Caminos, it has never happened to me. And what's wrong with rolling out your sleeping bag on a bench/churchstep for that highly unlikely night?
You are on the Camino for several reasons, perhaps one of them is to get away from a life of regularity and rules/must-do's. Why bringing them on to the Camino, and spoil a unique experience? Looking for new ways for your life? Then you must jump... Many unexpected things (can) happen on the Camino. Maybe coincidences in your life? Then remember:
Coincidenses are God's way of staying anonymous...
(Mahatma Gandhi)
Jump.
Buen Camino!
EDIT: FYI: I am most likely on the CF from early May, starting in Burgos (I think): No pre-bookings whatsoever...