I determined that the Euskotren E2 line has a train from San Sebastian to Hendaye every 30 mins at I think :18 and :48 past the hour. The ride is 37 mins. The Euskotren station in Hendaye is across the street from the SNCF station. I bought tickets for the 11:something TGV. We will take the 10:18 train from San Sebastian, or perhaps the 9:48. THanks for the help everyone.