What are my chances on Stanford, UCLA, USC, Cal Berkeley, or Vanderbilt with what I have?

You have a really good shot at all those schools! But getting into Stanford is really unpredictable. You are definately qualified to apply but remember...NO ONE who applies to Stanford has guranteed acceptance. It is as good as (if not better) than most Ivy league schools. Anyway, I believe Stanford is more known for medicine than engineering (I may be wrong). Also, If you apply to private schools, it is better to take BOTH the SAT and the ACT. Lastly, just remember to not get lazy during your senior year. GOOD LUCK :D