I know it's a long walk for both of you, but the whole place runs on UNC, UNF, NPT, and even ACME
I don't think I've ever needed to use E-Bay for nuts and bolts, except for the really odd sizes, like the extra-fine thread 1" on the M19 axle nuts, and 12 gauge on the Carryall side panels and doors, plus the occasional UN form left hand thread die nut or tap for a troublesome wheel stud or lug nut.
I do make a point of salvaging every original fastener I can though, as many of the head styles that were common 70 years ago are just no longer around.