Plans B, C ...
Ok, so it seems Plan A wasn't as successful as you'd hoped. So enjoy the company of those who can make it to the Giveaway--even if it's only two. Then consider implementing other plans such as ...
Plan B: Find an assistant, like Jimmy's Leisurelady65, who will pack and ship the items to those who would appreciate them and take good care of them.
Plan C: Have UPS or another trusted delivery company pack and send the items to those who are unable to travel to CA. Sellers could fund all costs, including your travel allowance, through Paypal.
Plan D: Make arrangements with the Vacuum Cleaner & Floor Care Museums in Missouri, Ohio, and Oregon to make donations if they will fund the s/h.
Plan E: Contact companies such as SC Johnson and Aerus to assess their interest in paying you for vintage items & s/h for their historical collections.