When planning a relatively long road trip, there are three things to consider in order to make it a success. Apart from having a good map, you'll need to consider which snacks to take, what music to play and who should come along.
The best snack for road trips is beef jerky1. It's filling, goes well with not only carbonated beverages but water as well, and, most importantly, it doesn't produce crumbs. If travelling across the United States from coast to shining coast, you'll find that beef jerky varies greatly by region and they'll vary according to colour, texture, moisture, taste, and MSG2 content.
Quality is judged upon how raw the jerky looks and how natural it appears
Texture is judged by how tough or tender your beef jerky is. You can use either your mouth or your hands for this.
Taste is purely subjective - if you do find a brand that you like, keep the wrapper so you can have a better chance of finding that same brand at 3am after the end of a long caffeine session.
The ultimate rule is that you must find your own jerky zen.
Care must be taken in the selection of the music not only for your own listening pleasure, but the sanity of your travel companion. The music should have a good beat you can dance to without being monotonous. Rave music would be a bad choice. Look for artists that spark interesting thought and conversation. The painted desert might be beautiful, but after two days of it, expect some of the novelty to wear off.
These should be people that you know, that you like, and you can comfortably sit through their shift behind the wheel. Wannabe Mario Andretties3, or Road Rage Rockers are never good choices for long journeys. They will likely scare the heck out of you when it is their turn behind the wheel and they won't let you drive in peace when it's your turn behind the wheel.
You should have enough in common that you don't argue over things like rest areas and restaurants and enough differences that there is always something to talk about - like music or beef jerky.
One final top tip is never strike up conversations with strangers at rest areas. They might find out that you're exactly what they have been looking for in a victim.
For more advice, check out Not Getting Lost on Your Way to Somewhere New.