Just helped a family member prep for their first long trip in the car. Their kit included:
CCS Adapter (Tesla OEM one)
J1772 Adapter
OpenEVSE (which has native 14-30 / 14-50 plug on it)
Adapters to NEMA 5-15 (wall socket), L14-30, and TT-30
Apps / accounts on Electrify America, Chargepoint, EVgo, EVconnect, Plugshare and A Better Route Planner.
And a printed list of all the SC, CCS, Tesla destination, Level 2, and campground charging opportunities on all three legs of their drive.
Oh and of course spare tire, jack plugs, jacks, tire inflator, emergency water food and blankets, etc.
Window washer fluid, scrub stick / squeegee (keep the camera location especially clean), washcloth for wetting and putting over hot supercharger handle.
But 2000 miles in and it's been only superchargers and L2 chargers at their preplanned hotel stops used so far. Then again, they have been following interstate and major US highway routes with good SC coverage.
Be as prepared as you want, or not, it's up to you.