Hi Jo,
I guess 'beauty is in the eye of the beholder', but I found the Le Puy route quite beautiful, especially from Le Puy to Conques. There are far fewer people walking than on the CF, and the gites are smaller, but I found there was a real community feeling amongst the walkers.There are also quite a lot of rather beautiful historic towns and villages that you pass through in places.
Your best bet for knowing about accommodation is getting hold of a Miam Miam Dodo guide (which you can get by mail from CSJ), but I wouldn't get it yet, as there might be an updated version available next year. There aren't as many choices as in Spain, and in places you have to make a call like, do I walk 17km or 32km? The Miam Miam Dodo guide usually lists which months a gite is open, and many are open from about 'Easter to All Saints' though some are open year round. It might not be quite so necessary to book in September: I walked in May which is full of public holidays and a very popular month for walking. However, there isn't the same choice of accommodation as on the CF, and if you don't book, you might end up having to pay for a more expensive chambre d'hote. Here is a list of gites- though without a map it doesn't give you any idea of distances:
http://www.xacobeo.fr/ZE1.03.Puy_gites.htm
The MMD does have maps but doesn't show much about altitudes. There are altitude stage maps in some tourist offices. You can also go to the godesalco site
http://www.godesalco.com/plan/podense, plug in a start and finish place, and print off your own altitude charts. There are some rather big 'ups and downs' in the first few days from Le Puy, but once you have left Conques behind, they become more 'rolling' and you even get places where it is 'flat' for a few days. The Aubrac Plateau is a 'high' point and you could get bad weather there anytime. Quite a lot of the medieval towns/villages are on top of hills so you climb up to them, then down again!!
I never took a mobile phone but I had a phone card I could use in phone boxes. You can also ask many of the tourist offices to book ahead for you and most do that willingly. I probably will take a mobile phone with a French SIM card next time though, as the card didn't work in all villages, and not all villages had phone boxes, and often I got answerphones but couldn't give a number to ring back...
You don't need to worry about the cold as the gites are heated in France, and pretty much always have blankets available. There are good kitchens in most of the municipal gites, but in more rural areas, the private gites tend to offer "demi pension" which includes your evening meal and breakfast, and they don't necessarily have a kitchen you can cook in.
Well, that's a start. Have fun!
Margaret