We have decided to use the train for our travels. The high speed trains do not seem to have opened up times for our travel dates yet and seem a little hard to figure out because of it. If anyone has some info on how to use the trains and what trains are the best I would really appreciate it. We would like to travel on April 13th to Barcelona from Valencia-what train and now often? Then from Barcelona to Cordoba on April 15. Then from Cordoba to Granada on the 17th. Then from Granada to Malaga on April 19th. There will be 6 of us traveling together.
Just for research purposes, I would recommend using the loco2.com website to look at options for trains - it is a nice, user friendly website. Pick some sample dates to see the times and prices available. For example, I just put in Valencia (any station) to Barcelona (any station) on January 26 (since your April 13 date is also a Saturday) and it came up with many options. Hopefully this will be helpful just to get you started. Good luck!
Check the schedules on the Deutsche Bahn website for the correct day of the week for each of your planned travel legs. It is about the easiest place to find schedule info. Dates in early March should work, but the day of the week does matter.
When you're ready to check fares and/or buy tickets you'll need to use Renfe or one of the companies selling tickets at the normal cost without excessive fees. Those include trainline.eu or loco2.com. Do not buy from RailEurope, which is almost guaranteed to cost you more.
For Cordoba to Granada I think you may have a choice of a rail/bus combo or an all-bus combo. As of the most recent report they were still working on the rail line that will allow express-train service into Granada.
Schedules don't change. For planning purposes, I use renfe.com and choose the day of the week I want to travel. If I want to check prices, I will look as far ahead as trains are offered, knowing that some trains may not be shown. Because you're traveling during Semana Santa, there may be more trains scheduled, certainly not fewer.
I also recommend purchasing your train tickets from loco2.com. It's a very easy site to use; I had no problems with them, and they always responded promptly to any questions I had.
And I recommend ALSA bus to and from Granada. The buses are modern, air-conditioned, clean, and comfortable.