Long road trips at sustained highway speeds put more stress on a vehicle than typical commuting. Components that were 'fine' for short trips can fail under sustained load.
Pre-trip inspection: battery test, tire pressure and tread, coolant level, oil level, brake fluid, washer fluid, all lights working, spare tire pressure.
Pack: phone power bank, water bottles, snacks, blanket, basic first aid, flashlight, road map (paper backup for cell-dead zones), small toolkit, jumper cables or jump pack, emergency triangles.
Route planning: identify gas stations every 100–150 miles in your route. Note major rest stops. Know where the nearest hospitals are in case of medical emergency.
If you'll be in cell-dead zones (mountain passes, rural sections), satellite communicators or cellular boosters add safety value.