Certainly change the oil and oil filter, and the air filter. You could also replace the coolant, and even change the radiator hoses and clamps. Have the air conditioning serviced, and maybe replace the fluid. Check the brakes for wear and replace if they’re down, replace the brake fluid. Also check the tyres, including the spare, for wear and any signs of damage, and replace if they need it. Obviously set the tyre pressure to the correct pressure for the load it will have.
Check for the Kia dealers that will be in towns along your way, so you can have it serviced if needed while you are away. And regularly check all fluids on the trip.