Hi Don
I am sure you'll have a great time. I have been in that area many times and will go back for more. The 'Pueblos Blancos' in the surrounding mountains are very photogenic and will offer different kinds of opportunities: street scenes, architecture, portraits, cats. The mountain scenery when you go inland is spectacular, especially around Ronda. Ronda is famous for its bridge and the oldest bull ring in Spain and the surrounding area is less touristy than Mijas and the coast.
I don't think Tangier and Cordoba are in day trip range, but Seville and Granada are certainly worth a visit (Granada would be my favourite, just). Camera's are OK in most cathedrals, but tripods often require a special permit to be arranged before your visit (and I don't know what the cost would be).
April is great time to go: not too hot. Don't worry about crime too much, just take the usual precautions, don't leave valuables on display in your car.
Have a look at my website for some examples of what kind of things you could shoot:
www.vanruitenbeek.com