Officially, the area is the Santa Cruz River Park Disc Golf Course (see Google map). It is a nice big, flat area. Very quiet. Good parking. The trees are too small to provide much shade, but still it should be a good place to play on cloudy or cool winter days. Restroom facilities are a few scattered port-a-potties.
The location is north of the Arizona School for the Deaf and Blind, on Speedway, west of I-10 and the river. To get there you have to go around the school. Starting from Speedway and I-10 proceed west to the light at Grande (which is the main entrance to the school). Continue on Speedway to the next light (Riverview) and turn right.
Follow your nose and stay on Riverview. Riverview will curve around to the right and then a bit later there will be a fork in the road. Follow Riverview by taking the left fork and then very soon, on the right, you will see the entrance to the park (first photo, below). As you go into the park you will see the playing area on your left (second photo, below). A little beyond that there is a parking area.
Click to see larger image.