It’s a very good time of year to choose in my opinion, my first venture onto the
Camino Frances in November 2015 was from Leon to SdC.
In normal years there was no lack of accommodation, although there was a reduced choice - the free market balanced supply and demand very well.
Recently it has been reported that booking ahead was advisable - but that was largely in (many) posts in July and August with lots of Spanish peregrinos and many more Spanish folks choosing to holiday at home. Those months are renowned for the ‘bed race’ in any case.
A reasonable compromise may be to book your first couple of nights and take advice from the hospitaleros with respect to your future plans. Spontaneity is an important part of many people’s experience of the Camino.
November through March is my usual Camino season. I book my first night, wherever I’m starting out from, then take it as it comes. I’ve never failed to find a good bed.
Be prepared for rain.
Budget for a couple of (relatively) up-market stays.
Don’t over-think the logistics. Even some who I thought must have evaded their full-time carers somehow managed without drama.
Try to spend a couple of days in Santiago. It’s where you’re going and worth experiencing in a relaxed manner.
Check out the excellent recent thread on the virtual queuing system for a compostella, if you want one. You might be the only one in town who understands the system.