Roughly it is about 800 km from Barcelona to Granada. And about 90 km from Granada to Malaga.

Driving in Spain is wonderful. The speed limits aren't enforced on the highways. From the map I'm using it appears that it's not a major highway on this route, however, it should be decent highway. It doesn't appear to be a toll road so that will help on expenses.

With their gas prices, I recommend getting a diesel powered vehicle. You really won't notice much performance difference in the cars, except at the pump.

Have fun...I was driving around Spain in September.