In no particular order:
Points, distributor cap & rotor, fan belt, dashpot oil, motor oil, spark plugs, plug wires, tools, jack, lug wrench, spare tire (although I never carry one), brake fluid, jumper cables, antifreeze & maybe a 1 gal gas can (filled, of course!).
You can probably get by without most of this list.....it depends on the condition of your car and your luck (or lack thereof) on roadtrips. While I have a non-Spridget engine in my Bugeye, I have driven cross country many times and never had a flat or any major mechanical issues. I did spring a decent oil leak once and cheap gas station oil in the middle of nowhere runs $4-$5/quart, so I always bring some with me now.