La Vélodyssée is the French section of EuroVelo 1, stretching more than 1,300 kilometres from Roscoff to Hendaye. Around 80% of the whole route uses traffic-free paths, which does not mean every individual stage is separated from vehicles throughout.
For a shorter journey, consider the 345 kilometres from Nantes to La Rochelle. Signposted in both directions, it follows the Loire estuary towards Pornic, then the Vendée coast and the salt marshes of Olonne. Small harbours provide reasons to slow down and stop.
The final roughly 25 kilometres from Marans to La Rochelle follow a canal, but they are not continuous asphalt. This stage includes rough and unpaved surfaces, with a less developed section near Dompierre-sur-Mer.
Allow for both surfaces and stops when choosing daily distances. Before setting out, read the stage descriptions, check current route notices and download the navigation track. That leaves more attention for the coast and less for finding the way.