Tips for cross-country drive?

Soon I will be driving from north Ohio to western Texas. I have never made a drive this long before, and I was wondering if you could give me any tips you have. For example, can you trust the gps on your iPhone to get you there? It says it will be a 22hr drive, but after factoring in traffic and rest stops I figured it would take more than a day. Where is the safest place to stop and sleep? Is it more realistic to just book a hotel for a night?

This next part will sound dumb but I have a phobia of tornados (yes I realize i need to expect them in Texas) and I'm paranoid that I'm going to run into one during the drive. What if I'm out in the middle of no where and there's no place to go inside? I get stomach pain just thinking about it.

Anyhow, and advice on making a cross-county drive will be greatly appreciated.

Make sure you go to the bathroom before you leave.

You might want to ask this over on "Travel" and not the law & Ethics board.
Legally you are free to travel state to state without papers.
You can also book a hotel and while GPS will work, I would also buy a map.
If you belong to AAA they can give you one free and mark your route.

How is this a legal question?

For long distances, I consider decent sized cities that are within the amount of time I want to drive that day for lodging so I have better dining options. Check fluids, belts, and hoses on your car. Check the tire pressure before you go (don't forget to check the spare). Make sure your windshield wipers, lights and turn signals are working properly too.

And tornadoes have been recorded in most states. Heck, I was caught in that exact scenario you are frightened of last fall in Indiana. The likelihood of this isn't good though. But it doesn't hurt to check the weather before you leave, especially if you have some schedule flexibility.