Hi. My family and I are planning to travel from Paris to Lisbon by train in May. This involves changing trains in Hedaye, France. The 2nd train is operated by Renfe and requires reservations.
On that 2nd leg, we would like to add a stop for a couple of days in San Sebastián, Spain. So, Q: Do I need to buy 2 separate tickets (Henday-San Sebastián, San Sebastián-Lisbon), or can I buy 1 ticket (Hendaye-Lisbon) and make 2 reservations (Henday-San Sebastián, San Sebastián-Lisbon) with a couple of days in between? (I've dug around a bit for Renfe's ticket policies, but haven't found much.)
Also, FWIW, any comments on San Sebastián? Worth visiting? Things to see/do?