Muchas gracias.
My original idea was to land at the San Sebastián airport, walk to Hondarribia, and stay up as late as I can to combat jet lag. Then get up early the next morning and take the ferry over to Hendaya to start walking to St. Jean. BUT... the ferry doesn't start till 10, so I think I will take the ferry over the day before and sleep in Hendaye. That's fine, too. I do want to start early enough from Hendaye to get to St. Jean de Luz early enough to get to Bayonne early enough to spend some time walking around Bayonne and enjoying what looks like a beautiful old central core.
The wikiloc tracks I have say Hendaye to St. Jean is only 13 km, so if I start around 7 am I can eat a late breakfast in St. Jean de Luz and then get to Bayonne in time to have most of the afternoon there, at least that's under the best of circumstances!!! Does that make sense to you, Nuala?