Caravaned to Florida one year. Shake down cruise for the old man's Duster.
Ran fine on the way down. On the way back, kept running out of fuel. Pump was pumping, but coming up dry. Somewhere along the way, Pop picked up a rat's nest in the tank. Best bet was a gas station changed a hose on a pump and Pop was the lucky one to pump it into the tank.
A spare fuel filter is never a bad idea. Pop dropped the tank, cleaned it out and used a metal filter cut in half as a new strainer.
Besides the tools and the aforementioned parts I carry a spare starter, too, and a decent jack.
Other than that the typical emergency things: jumpers, fuses, roadside flares, etc.
Extra bulbs isn't s bad idea. Hate to get a stupid fixit ticket out of state for something dumb like a burned out bulb.
Extra clamps. Even some friction tape can wrap a hose enough to get you to a parts store. And takes up less room than spare hoses.
I've made several trips with just a spare, the jack, and jumpers, and gotten off lucky that I've never needed anything else. But I usually spent a day or more pre-tripping. Any possibility of dry belt or hose and it got replaced before I went.
Having a lock out/tow rider on the insurance policy is never a bad idea, either.