SF seems a good midpoint. The commute by car can be rough, say 30-40 minutes each way. For public transportation, she could take BART and you could take Caltrain.
The other day, the local news said the worst commute is the one from East Bay to SF.
What did not impress you about Hayward? Was it the price or quality of life? For prices, check out
craigslist: san francisco bay area classifieds for jobs, apartments, personals, for sale, services, community, and events. If you live in South Beach, you'll be close to BART and Caltrain. I just looked, and they have places under $1800, although 2 are studios, and 1 is a one-bedroom.