I was in the pub last night and was speaking to a young barmaid who's a student in London, studying to be a Vet. She was told by a customer that I hike so she sought me out because she and her boyfriend want to hike in France next year. It would be their first time ever and she asked me for a few suggestions. I had a very pleasant evening!
I suggested the first thing that they should consider is the ease of travel and then its cost. They want to fly because of their time constraints.
My suggestions were based on, easy to get to and not so easy to get to, was -
1 - Catch a ferry from here in Portsmouth to Caen, then hike on the GR36 route to Thury Harcourt following the right-hand track along the River L'horne, then cross the river and follow the left-hand GR36 (Variant) route back to Caen. This route will take them on a tour of the Suisse Normand area. If they study the free App map I suggested 'Geopotail' and once studied they could vary the route at will. As they live here this could be their obvious try-out one.
2 - The Tour du Mont Blanc. Planes to Geneva are usually keenly priced, then catch a bus to Chamonix, walk to Les Houches and then start the walk proper anti-clockwise from there. Ideal I think for a couple of young people, the Tour du Mont Blanc is such an international circuit. They would meet everyone from everywhere.
3 - The Stevenson Way (the GR70) from Le Puy en Velay to St. Jean du Gard. A bit more difficult to get to and perhaps less chance of getting a cheap fare? Fly to Clermont Ferrand or Lyon then catch a bus or train to the start point. Download (its free) 'Travels with a Donkey in the Cevennes' by Robert Louis Stevenson, read the book and then do the walk.
If you had been asked where would you suggest? Any good ones and I personally will be interested as well.