Granada does not have an official park and ride system.
This is my personal idea of the best park and ride.
Here are instructions:
The Sacromonte Abbey is about 40 minutes walk from Plaza Nueva (the absolute centre of Granada)
The Abbey has a large free parking area.
Leave the A92 at EXIT 253 (GRANADA ESTE - EL FARGUE) Drive through el fargue.
Take a left into Camino Viejo de El Fargue
Take the next left at the football pitch. (If you go past the electricity substation you have gone too far)
Drive down the road until you get to the abbey.
Park your car.
You are now at the M on this maphttp://granadamap.com/4.htm
If you want to get a bus get on a 35 which will take you to Plaza Nueva.
The 35 goes every 30 minutes.
For more frequent buses walk down to Cuesta Chapiz where there are buses every 15 minutes.