Believe it or not, there is an Amtrak stop in Cloverdale. You can take an Amtrak bus from either the Ferry Building or from Moscone Center (both near BART) to Emeryville. Looks like it takes about an hour and a half and costs $38 round trip. Not sure it goes every day, though, so check. Also, the station is not right in town, rather out by the 101 bypass. I don't know if there is a cab service in Cloverdale or not.

Has anyone else asked why you would want to do business of any kind (let alone skydiving!) with someone who won't answer your enquiries?