The AHLL Boundary map is here. It is a pdf, and large.
The address for the fields is the intersection of Alamo Heights Blvd and Devine Rd.
The “Park at Alamo Heights” is in the Olmos Basin, between the City of Olmos Park and the City of Alamo Heights.
From the North, get on Basse Rd, and just East of 281, take Jones Maltsberger and go South.
From the South, get on Hildebrand, and go North on Devine Rd. Devine Rd. and Jones Maltsberger are the same road.