Since I opened this question, I will provide an update. I arrive in Bilbao on the evening of Monday, September 18th. (this due to a strange flying arrangement funded by credit card reward points, with initial flight from Austin to Frankfurt, then down to Bilbao.) This week I booked bus and train tickets for my journey from Bilbao down to SJPP. Below is the best connection, but an early start, to get to SJPP with time to explore a bit.
Flix Bus - 0650 Bilbao to Bayonne, arriving at 0910 (about three hours)
SNCF Train -12:35 PM Bayonne to SJPP, Arriving at 13:40 (just over an hour)
The combined tickets cost about $25 US a great value for travel. The side benefit, the bus/train ride will allow me to see the countryside.
My only regret is that I will have little time to enjoy Bilbao. Friends in my 'over-the-hill' local men's coffee group here in Seguin, Texas, shared with me what a wonderful city Bilbao is, especially the Gugenhiem Museum. So poor planning on my part. I was concentrating on getting a bed in SJPP, Orrison, then Burguete the first few nights on the Camino, and at this point do not want to risk those reservations. After Burguete for the remainder of my walk to Santiago then on to 'the end of the earth', I plan just to 'wing it' for hostels/hotels. That will allow me to fully enjoy the 49 days I have available to do my pilgirmage.
In Bilbao I did change my hostel to Pil Pil Hostel Bilbao, which is located about three blocks north of the bus station.
The couple of hours in Bayonne will allow time for lunch and getting from bus station to train station. The arrival time in SJPP allows me time to find my hostel and enjoy the town a bit.
As usual, thanks to all of the pilgrims before me, your sharing information is invaluable. I will follow-up as I actually travel to share my experience.
...Ken