Welcome!
While I enjoyed every stage of this camino, the ones after Aire-sur-l'Adour weren't near the top.
Here are the number of days it would take, on average, to walk between towns with train stations. Three days will be challenging ... but if you can pull five there are many more options! I've bolded the ones I'd recommend you consider.
- Le Puy to Aumont-Aubrac (4 days)
- Aumont-Aubrac to Decazeville (5 days to Conques, then taxi to Decazville)
- Figeac to Cahors (5 days via the Célé variant)
- Cahors to Moissac (3 days)
- Moissac to Aire sur l'Adour (5 days)
- Aire to SJPP (6 days)
The first would be great for feeling like you are part of a pilgrimage journey. A lot of people start from Le Puy, and there's a nice sense of community. But you might feel as if you've only just begun, and then it's time to end.
The second passes through Conques, one of the most iconic stops on the Via Podiensis. You also pass through some nice medieval towns tucked away in the woods. You can end in Conques (five days) and take a taxi up the hill to Decazville, then train out.
The third, a variant through the Célé Valley, is a stunningly beautiful and magical walk through a medieval landscape. You would also begin and end in two towns with decent transport options, Figeac and Cahors.
But it is also a variant, and most pilgrims take the direct route. I only met one to three pilgrims a day. If you're looking for the groups like on the CF you won't find them. It might not
feel like a camino in the same way ... though it very much is one. You and your wife will get an excellent feel for walking in France, however. It would be my personal choice if I could only do a short walk.