I walked the Le Puy route in June 2013, arriving in SJPP July 4th, then continued on to SdC, arriving Aug. 5th, then went on to Finisterre. I also went alone and I'm your age. I enjoyed the Le Puy to SJPP route very much, specially the first 2/3rds of it. Although the hiking was harder in France due to the rougher terrain (and the mud - there was lots of rain this spring in France), the scenery was fantastic, specially from Le Puy to Conques, and the trail was not crowded. The French people I met were very friendly. Although the food was more expensive than along the Camino, the food was fabulous and they used high quality ingredients and served regional specialties so there was variety - not the same pilgrim menu served everywhere like along the Camino. The pilgrim hostels were more expensive than in Spain, but accommodations were usually nicer. The hostels are also usually smaller, so you need to call ahead to reserve a bed most of the time.
I also appreciated that in every town I walked through, the churches were always open, there was a public bathroom (with toilet paper!), and a public water source. I used the Miam Miam Dodo to find food & lodging, and Allison Raju's book for cultural and historical information. Her maps were useless, so I bought the Federation Francais GR 65 books. Although they are all in French, they are easy to understand and have very useful topo maps showing the routes.
One very annoying problem was having my cell phone not work for long periods of time after having spent a lot for a French SIM at Orange and buying phone credits. I will never use Orange in France again - terrible customer service. Orange in Spain worked great, though. Another thing to be aware of: the food markets & shops in France close for about 3 hours in the middle of the day, so you must plan to buy your food for lunch before about 12 or 12:30, or you will have to eat in a cafe or restaurant.
On the last part of the Le Puy route, after Arzacq-Arraziguet, the small towns often have no shops at all! My hosts at Aroue explained that this region has been losing population for decades, and can no longer support stores. Apparently, there aren't enough pilgrims to provide the business to keep markets and cafes going. It was often difficult to find food, and several hikers ran out of money because there were NO ATMs anywhere within walking distance. Not even Ostabat had an ATM. If you walk this route, be sure to have enough cash to get yourself from Navarranx to SJPP.
The only part of the trail where I encountered mean dogs was the French Basque country. Just outside Navarranx, one actually bit me. I had the impression that the Basques don't much care for pilgrims, and they use their mean dogs to let you know you are not welcome. I had no other problems with dogs along the way in other parts of France or in Spain. Mostly the dogs were friendly pooches who just wanted to share your lunch.
I enjoyed walking in France so much that my next walk will be from Arles through the Somport Pass, stopping at Puente la Reina.