To check your tires before a road trip check the air pressure using a tire pressure gauge and ensure they are not over inflated or under inflated.
The pressure is usually between 35 psi to 45 psi depending on the tire but the tire pressure for your tires will be in the owners manual or on the tires sidewall.
Also check the tires for any cracks or bulges and if you notice severe cracks or bulges in the tire then replace them before setting out on the long road trip.
If your tires are 10 years old or older then always replace them before the road trip as it's just a matter of time before they blow out on the road and leave you stranded or at least waiting awhile for a tow truck or it could even cause you to lose control and crash the vehicle.
Before setting out on a long road trip check your tires, engine coolant, check and change the engine oil inf needed, wash your windows, ensure you have a jack and spare tire with you.
Check your belt, hoses and other parts on the car to ensure they are in good shape and if you have bad radiator hoses or bad heater hoses or a bad serpentine belt then it's best to replace them now before you head out on the road trip.
Before setting out on a long road trip with your car you should check the car over to be sure it's in good shape to make the trip.
It's no fun breaking down so if something needs fixed before the long road trip you should make sure you get it fixed before setting out on the road trip.
Also it's a good idea to have towing insurance or have the extra money to tow the vehicle if you do have a breakdown.
Things you should check on your car before a long road trip are things such as belts, hoses, engine oil, transmission fluid, brake pads, brake shoes, brake rotors, brake drums, brake fluid, engine coolant etc
Check the tires as well and be sure the tires are properly inflated and make sure the tires don't have cracks or bulges in them and if they do you should replace them.
Also carry extra engine oil with you as well as engine coolant in case you need to add more engine oil and engine coolant.