I just wanted to put a warning out to anyone who is trying to prebook trenhotel (overnight) train tickets via the number on the Renfe website . Here's my story-
I was worried about being able to get tickets for an overnight train and didn't want to wait until I got to Spain to make the booking. I tried to book over the internet, but they wouldn't let me book an overnight train via website for an unspecified reason. So, I tried the 800 number on the Renfe site (located in Illinois) which connected me to Rail Europe . (I didn't know this at the time) I booked ahead for a 2 person sleeper from Valencia to Granada and had the tickets in my hand a couple of days later. They didn't ask me if I already had a rail pass or anything. They said they had had problems with the Spanish rail system's booking system, but that my tickets had gone through, no problem. Just in case, we checked with the ticket counter in Valencia when we got there & showed them our reservation. They said no problem, that's all we needed. So, we board the train at midnight, and the conductor says our tickets were not correct. To make an already long story shorter, a nice Spanish woman who spoke English (we speak limited spanish) in the room next to us helped us straighten it out, but we ended up paying about 75 euro in cash on top of what we had already pre-paid to stay in the room!
The officials were very nice, and I'm sure would have accomodated us, but it was quite nerve wracking.
The other group in our party booked a couple days before in Spain and had no problems. If you aren't traveling during a busy season, that is definately what I would reccomend.