Nearly everyone who walks the Le Puy route carries the Miam Miam Dodo guide with them, and this has route maps. (It is available from CSJ.) MMD have a website that includes maps and some gite listings. http://www.chemindecompostelle.com/Selection/CarteFrance.html If you click on a rectangle, it brings up more detail for that area. It is much harder to get internet access in France than in Spain though, so you wouldn't be able to rely on regular access to this site en route.
The MMD book also has listings of pilgrim accommodation, including gites, chambre d'hotes (like bed and breakfast) and a few hotels. In France, unlike Spain, it is usually preferable to reserve a place a day or two ahead, or you might miss out on a bed in the gites and have to pay more for a chambre d'hote.
Camino Frances Sept/Oct 2012
Camino Finisterre Oct 2012
Le Puy Route (Le Puy-en-Velay to St Jean Pied de Port) April/May 2014
[Kilimanjaro Sept 2014]
Le Puy Route (Le Puy-en-Velay to St-Chely d'Aubrac) May 2015
[Stevenson Route, France - April 2016]
The Way of St Francis (Sansepolcro to Assisi) May 2016
[The West Highland Way, Scotland - Sept 2016]
[The Kerry Way, Ireland - March 2017]
Camino Primitivo (Oviedo-Lugo) end April-mid May 2017
[Everest Base Camp Trek, Nepal -- October 2017]
Stating the obvious here but it depends on how fit you are, the distances you want to do (or are capable of sustaining over several weeks) and how many rest/sightseeing days you will need. The French "Chemin de Compostelle" map set/booklet (recommended!) by Michelin breaks the route into 32 stages but I feel its a bit ambitous given the distances /elevation gains for some of the stages. Bearing in mind the 32 days does not not allow for rest days averaging 23km per day or about 26km/day if you take 3 rest/tourist days.
The Le Puy Route is beautiful but a number of stages (particularly during the first two weeks) are surprisingly challenging (doable but easy to overestimate how far you can walk). For that reason I feel a realistic minimum timeframe is no less than 36 days (including 3 or 4 rest days) but you unless you are very fit and not prone to fatigue you may find you are pushing yourself too much particularly the first two weeks. Personally I would recommend extending it about a week i.e. allowing about 6 weeks (about 42 days including about 4 rest days) to complete the full chemin from Le Puy to SJPdeP and allow additional time if you need to allow for travel days either side of your trip. 42 days (including 4 rest/touristy days) means you would need to average about 20km/day. Can't remember how long I took exactly but I think it was about 42 days and within that I had all the rest days I needed and was able to ease into it at the start.
By the way this is a brilliant planner for the route: http://www.godesalco.com/plan/podense - you can break the route down into stages and produce elevation maps from it. It shows which villages/towns have accommodation (not completely up to date but its generally accurate). At any rate its really useful for getting an idea of how many days it would take you or for just getting an idea of the type of terrain you will be coming across day by day.