Hi Damian
Sounds great, hope it all works out.
You can buy tickets for the Alhambra from 13 weeks in advance and they get booked up very quickly. You pick your time by the hour and there is a lot to see. I think we got tickets for 11 a.m. They are €13 for a General visit which entitles you to see everything.
It's motorway nearly all the way there and is then signposted but remember the way for when you come back down to the motorway. Look at
http://www.servicaixa.com/nav/en/mucho_mas/granada/alhambra_y_generalife_09oz/visita_general/index.html. Sorry that maybe won't work but try
http://www.servicaixa.com anyway.
cheers, Jean