Jeff,
The trip to SAC reef is really not that hard. Once you top off in Ensenada and assuming that you cruise down to Geronimo at 7.5 knots (trolling speed), you would have plenty of fuel to fish a couple days at the reef and return to Ensenada. Of course, going that slow requires more time and to do it right you might consider anchoring at San Martin each night in between Geronimo and Ensenada.