I drove around the usa this summer, about 15,000kms. My advice is this:
-Change the oil right before you leave
-Make sure your tires are good and balanced
-Check for steering play/suspension play
-Keep a basic toolkit with you
-If you don't have a cell car charger get one
-Check your tranny fluid and if it's dark or has never been changed, have it changed.
I drove my 95 on said long trip and it hit 200k miles on the trip. I didn't have one issue except for a y pipe gasket and a cracked windshield.
If it's running good, you'll do fine.
Also if you feel tired pull over and take a nap. There are a lot of rest stops and most have free coffee and muffins in the morning!