I am going to Spain in September and would like info on the trains to help me plan: 1. For the following routes: Madrd to Sevilla; Cordoba to Granada; Granada to Madrid; Madrid to Barcelona Question on reservations - is it best to make them in advance, or can it be done a few days before? Is there flexibility on a reservation once made, allowed to change the time? 2. Sevilla to Cordoba - is a reservation needed? Trains are quite frequent. Thanks in advance.