If you want good restaurants in a walkable, safe, close area.. try Alameda. As for Oakland, A's games are safe, Jack London is safe, Lake Meritt is safe. Stay on main roads, use common sense, don't stay out past 11pm. Also consider nearby Emeryville for outdoor mall, restaurants, good safe walking trail along bay.

Oakland also as a must check out jazz club/restaurant called Yoshi's. If you got time, definitely don't be afraid to go check out the town.