I did a photo excursion to central Spain in October a couple years ago, and I've also been to Granada in the summertime. The light around Granada is VERY intense. You'll find yourself wishing one moment to have a slow film like FP4+, and another to have something fast, like TMAX 400. If you want a one-film-fits-all film, try the T400CN chromogenic film. You can shoot it at 100 most of the time, and you'll have gorgeous (but dense) negatives. For when you need the speed, drop it back to 400 again, and you'll still have quite printable film.
Also, because Spain is on continental time, but is actually west of England, the sun rises and sets an hour later (by the clock) than it should. You'll have daylight until about 8pm or later, even in May. I would definitely limit the gear you're carrying to something normal, and something wide, no tele anything. If you can swing something wider than 35-40mm equivalent, I'd do that. Maybe pack the EOS with a 50 and a 28, and take the XA for pocket snaps. Just to give you an idea of what I hauled around with me (my trip was a dedicated photo trip), I had my Hasselblad with 50, 80, 120, and a Superwide with the dedicated 38mm. I also brought an Xpan for panoramics. Streets in the old cities of Spain tend to be very narrow, and if you take a wander through the Albaicin (the old arab quarter of Granada, which is worth the effort, just be careful of your gear and your wallet), there are lots of interesting buildings to take in. There is an old Arab marketplace whose name escapes me, but it is nestled down an alleyway, and the courtyard in the marketplace is still shaded the same way they did it hundreds of years ago, with positionable canvas shades that they move with the sun.
There is also the cathedral, which houses Ferdinand & Isabel's remains, the Sacromonte hill, with gypsy cave dwellings, the La Cartuja monastery, and near the Plaza Nueva are 11th century Arab baths.
When you go to do the Alhambra, plan an entire day for it. Book your ticket as early in the morning as you can, take the tour, and then stay as long as you can wandering around taking photos. There is so much to it, you'll never see enough. Make sure to take in the gardens - there are some beautiful and tranquil spots, with little fountains and reflecting pools nestled in the trees. One of the fountains was designed in such a way that the single stream coming out of it has just enough force to suspend a small round object, like a walnut or a pebble - look and see if you can see it. Of course, there is the famous courtyard of the lions. For a dramatic change of pace within the Alhambra there is the Charles V palace - itself a marvel of Renaissance architecture, but because it is plonked down in the middle of the Alhambra, it gets rather short shrift. At the least, stop through and take in the circular courtyard.