78759, 78727, I guess 78729 too are low yield. $1800/ month for $300k is about right for these zip codes.
78613 & 78717 is medium yield. $1900/ month for $300k house.
78660 is high yield. $2300/ month for $300k house.
Newer houses (less than 10 years old) have higher yield but small lot 6000-7500 sqft.
Older houses (70s-80s) have lower yield but large lot 9000-12000 sqft.
Ideal rental houses are between $250k-$350k.