I used the
VĂ©zelay guide of the Dutch Association of Saint James (available in English as PDF or in a printed version) for the variant Nevers in 2016. It got me in SJPdP without hick-ups, so well recommended. They update it once a year.
I got by on 30 euros a day, but that was the limit of my budget so I went rather basic. If you can spare a little more, life on the road will be easier. Do plan ahead at least a day (especially for weekends and mondays) in France when it comes to accommodation: call or let someone call to make a reservation so they know you're coming.
Keep some space allocated in your pack for food and drinks and be sure to buy it when you can: nothing worse than arriving somewhere to see everything closed or without shops/restaurants, and that will happen.
I carried half a dozen hard boiled eggs as a rule, and always had some tins of fish and fruit ready. Bread is usually available everywhere, but again: get it while you can. Use the guide to find out where to shop and/or eat on the way.
Happy planning and bonne route!