I've looked at a few sites to try to figure out how to get to Granada from Barcelona, and how long it would take. On the Renfe site it mentions "trenhotel", an overnight ride from city to city. Is this a true sleeper train or just an overnight ride (about 11 hours)? Also, I saw that there is a twice daily train that takes about 7 hours. Where can you go to book this? What is the best option?
The "trenhotel" is a true sleeper train that has beds, couchettes, and seats at different prices. If you've never travelled on a sleeper train before though, be warned that some people can't sleep on a moving vehicle, even in a bed. The best place to book both trains is the renfe website, there's a detailed description of it at http://www.seat61.com/Spain-trains.htm#How_to_use_www.renfe.com
"What is the best option?" My husband and I took this route a couple years ago, and we researched train, bus, and even renting a car. In the end... we flew. Budget airline Vueling (among others, possibly) often has low airfare for that route and the flight time isn't long at all. Just wanted to throw that out there for consideration if you hadn't already.
i took a sleeper a few years back from granada to barcelona, and pretty sure the reverse also exist. the train leaves granada around 8 or 9, and arrives in barcelona about 8 in the morning. i don't like to buy train ticket on line just to avoid panic. if you spend at least 1 overnight in barcelona then you can buy the train ticket on your arrival, so you don't have to go back to the train station again. you may be able to find travel agency in barcelona sell train ticket too, just look around and ask.