What does one do to reattach the little rubber bumpers (hood, doors, windows, trunk) that have lost the little connecting base part? Is there a rubber glue of some kind that can come to the rescue?
Don't bother. Most of them have hardened over the decades and aren't doing much good. Replacements aren't that costly. Many of them can be found at Mac's hardware, auto parts stores, or some surplus stores. Or new parts are available at RT Specialties, Stephen's, Year One or other sources.