It sounds like you are still figuring out where you want to live and are also concerned were your children will attend school.
If you are looking to check which schools a candidate property will pull to I would suggest you take a peek at http://www.SchoolAndHousing.com
Based on property address, SchoolAndHousing provides attendance area schools (Public, Private and Daycares) along with useful performance statistics and other information.
HOWEVER, before making an offer/signing a lease you should call the School District to CONFIRM the schools the property will feed to!
Regarding the Tracy area it may be best to refer to: http://www.tracy.k12.ca.us/schools/Pages/SchoolBoundaries.aspx