Hi this is Wayne of the loud font...
I have the Rick Steves Bbook, 'Sevilla, Granada & Andalucia' copyright 2017 for text.
It uses the bus naming of C1, C2, C3, C4. These busses' names have been changed to C30, C31, C32, etc. The change might have been December 2018. Although every now and then a bus stop still has the C1 system on its signage.
We are on our third day and ran out of "Rick" suggestions, so I googled the basilika across the street from where we are staying. WOW! This should definitely be in his book. Google San Juan de Dios, read the tripadvisor reviews. They are so clever, they made me excited to visit our neighbor.
By the way...basilika, or bazilika, or bazilica means a church with extra ordinary beauty. So it is always worth checking out.
I have been to many churches, basilika, cathedral, monastery, and chapel. This is in a class of its own. I thought I had seen the pinnacle of Baroque when I saw a mamouth church outside of Ololouc, Czechia. This is the baroque that broke the style. (Sagrada Familia, Chartrer cathedral and the Aya Sofia are not baroque in style.)
How to get there. Very easy. Get to the cathedral in Granada. Find Calle San Jeronimo, it Ts into the cathedral. Put your back to the cathedral and walk until calle San Jeronimo Ts (at calle Gran Capitan/calle San Juan de Dios). This is a university neighborhood, so there are lots of students, and is very safe. At the T, go across the street and turn right. It is about the third building on your left. The entrance is on the left immediately beyond the old stone structure itself. Enter through the small garden. Entrance fee was 4€ as of 28 March 2019. Audio is included.
Don't leave until you get upstairs for a very close view of the relics and momento St John of God. And don't leave until you see the 4 minute special animated presentation in the naive.
We have only visited once, the stairs going up were gladly opened upon request at half past the hour, and the 4 minute show started on the hour. I am pretty sure that that door gets locked and people shooed out of the upstairs before the animation can start. Someone could get injured or the automated equipment damaged if left behind.
This is a must see. Using Rick's method, I would give it three triangles. And list it immdeiately below the Alhambra. Maybe he doesn't list it because it is 7 short blocks from the cathedral and people don't have time for this short walk or they become frightened by narrow streets and grafitti. Trust me, you know me, it is a short walk. Straightish. And safe.
On the way back consider calle Duquesa as an alternate route home. It leads you past Jardin Botanico, and ends at Plaza Trinidad. From there turn left (east with a compass, but maybe not on your map) and head back to the cathedral.
Enjoy your travels,
Wayne iNES