@gigibarry - I walked from Swansea to Portsmouth then ferry to St Malo. I then crossed to the Atlantic coast near St Nazaire via Rennes along river and canal towpaths. I began in autumn and walked for about 3 weeks, finishing in Redon. I returned to Redon in the spring and basically followed the coast south via Pornic (small town where my soldier grandfather is buried) and La Rochelle to Royan. Ferry across the Gironde then the Voie Littorale from Soulac to Bayonne. River Nive footpath and minor roads to Bidarray - about 20km south of St Jean. That stage took 4 weeks in May. All fell apart there after I slipped and fell awkwardly with the result being a slipped spinal disc. Taxi to St Jean, 4 days recovery at Beilari, then limped home by train/plane. Returned six months later to walk the final 20km. I carried a tent and camped everywhere except for hostels in Rennes, Rochfort and La Rochelle. From St Nazaire to Royan I walked on minor roads which tend to be almost traffic-free in rural France outside the July/August holiday period.
Edit: the above was written in a bit of a rush at Trondheim airport. I also stayed in a hostel in Dinard, a hotel in Arcachon, and an F1 motel in Bayonne. Mostly 'camping sauvage' though as few French campsites are open in May. I navigated using pages from a road atlas and occasionally the mobile version of the IGN mapping website. Government cartography, free to use and excellent on detail.