It's very unlikely that you'll get into a UC school with average stats, unless you have spectacular life experiences or extracurriculars.
UCSD, UCD, and UCI accept very few (if any) out-of-staters every year.
UCLA accepts only about 15% of their class from out of state and the people from out of state usually are from top schools with top stats.
UCSF accepts 20% of their class from out of state. Be warned, however, that UCSF has a reputation of rejecting in-state people with 3.9s and 35+ MCATs.
Your best bet is to stay away from UC schools if you are from out of state, unless you have top stats.
Good luck.