Cell phone coverage is much improved in Bear Valley. However, you have to keep in mind that we are high in the mountains.
On your drive to Bear Valley you should experience good coverage through the Central Valley. But once you get into the foothills, service becomes spotty. Most services drop out between Copperopolis and Angels Camp.
All the major services will get reception inside the Angels Camp city limits. But once you leave Angels Camp most services drop out. Verizon and AT&T will come back in inside Arnold then you will lose all services until Tamarack (2 miles west of BV).
Once in BV, Cingular, Verizon, AT&T and others will come in. But signal strength varies throughout the town.