U.S. rental car locations really lean hard on the 'or similar' language in their vehicle rental classes. But their are many typical SUVs and crossovers that can reasonbly accommodate five adults and luggage. If this group could handle three hours in a Ford Focus or VW Golf, you'll be amazed how much room is to be had in an Explorer... and Expeditions are bigger still.

Airport locations certainly do higher volume and thus, imo represent a better chance of getting the vehicle you want. That's going to mean gtting back to SFO and paying a number of added taxes and fees but I can't predict what that will mean for you and satisfaction with the rental.

A little less trucky, but another 3-row vehicle that can work as 5 + luggage to suit your party, is the GMC Acadia and twin Saturn Outlook.