Not sure if this is the "best" way, but it's how I did it in May 2007:
I flew into Paris (CDG), planning to spend the night in Paris to overcome jet lag. It turned out to be a nice sunny day, so it was a good decision. Good day for walking around Paris & seeing some of the major sights.
I had purchased an Air France ticket to Biarritz (BIQ is the airport code), thinking it was leaving from Orly, but no, I had to head back to CDG. :roll: Anyway, it was a great price for the ticket, less than the 85 Euro for a train, & I was in Biarritz in about an hour. Then the bus ride to the train station in Bayonne & the train to SJPdP.
If I do this again in September, I think I will fly through to Biarritz on the first day, then overnight it in Bayonne or go on to SJPdP, then take my time the next morning & end up at Orisson (hopefully they won't "lose" my reservation this time. :?
Buen Camino!
Kelly