The Via Lemovicensis is a fantastic route, with just the right mix of solitude and people with the biggest hearts. Having said that, it is also a route that requires a bit more work and planning than you might be used to. As it is less travelled than for instance the Le Puy route, that also means less pilgrim infrastructure: fewer albergues, fewer shops, and more pavement and tarmac. But don't discount the Vézelay just because of that.
I got by on 30 euros a day in 2016, but that was the limit of my budget so I went rather basic (including tent). 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.
At all times 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. Eat what you can, where you can, and prepare for some meagre days
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.
I used the Vézelay guide published by the Dutch Association of Saint James. It's based on the Dutch translation of the famous "yellow" guide: Voie Historique de Vézelay by Monique Chassain. Great guide and also available in English. As a side note: there are two guides. One with the variant Nevers and the other with the route through Bourges. You can find them
here. Accommodation listings are available as a download
here
And just for your information: the Vezelay route has two places that still shine exceptionally bright in my memories and therefore come highly recommended IMHO. The first one is L'Esprit du Chemin in Le Chemin, 25 km after Vezelay on the Nevers variant. Arno & Huberta who run it are legends. The second one is the Moulin de Piis just after La Réole. It is an old watermill (renovated by local craftsmen) and a dreamlike location to spend the night. But remember to bring your own food and drinks if you sleep there. Small kitchen is available.
Waymarking overall is decent to very good, and with the aforementioned guide you won't have any problems. As I said, I loved it, and so do a lot of others. Check out
this thread by GunnarW, who posted a lot of pictures of the section Vezelay-Limoges. If you have more questions, feel free to ask, or PM me.