There have been several things I've come across during this road trip that I think everyone needs to know. If you plan on an extended road trip anytime soon, take this all into consideration.
Things you need (in no particular order):
GPS of some sort. For me, it's Google Maps on my phone. You will have a difficult time navigating to different destinations (such as cheap gas, points of interest, hotels, friends homes, food) if you rely on street signs. If you don't want it on your phone, or heaven forbid don't have a smartphone, get a Garmin. They make the best GPS devices. TomToms suck. Google Maps also helps you figure out what that strange building or landmark near you is called or what its purpose is.
Car phone charger. A multiple outlet docking station works great so more than one person can charge at the same time. Also, if it has USB port holes, you can charge MP3 players and/or cameras while driving, too.
Loose change. This comes in handy when you need to put air in your tires and also when getting on a turnpike with unexpected tolls.
Cash in different dollar bill forms. This comes in handy when your debit/credit card is flagged for being used in multiple states and is unuseable for a time. Also, it makes it easier to leave tips at any restaurants you eat at along the way without having to find a random ATM that will charge you $$$ for withdrawing cash.
Spare car keys. If you have a few extra, keep them in your pockets so you don't accidentally lock yourself out of your car at midnight in the middle of nowhere in the freezing cold at a creepy rest area.
Rain-X. This stuff is quick, easy, and it works. Just spray a little on your windshield, wipe it off, and you're good to go. Your rain will bead up and flick away from your windshield and you won't wear your wipers out by constantly using them in wet weather. Note: Misty rain doesn't come off as easy, so you will need your wipers. But this stuff is still fantastic.
Road Trip food and water. Water bottles, granola bars, chips, chocolate. It's great when you get the munchies and have no place to stop. It will save you money in the long run. Also, with constant temperature and elevation changes, you will get dehydrated fast if you don't drink enough water.
Tire Pressure Guage. This is seriously a lifesaver. It's small and fits in your glove compartment. As you go up and down mountainsides, your tires are going through a lot of pressure changes. Every few stops at gas stations, just check your air pressure and fill up and let out as needed. Most cars have the pressure you should be at either in the manual or on the inside of the drivers side door. If all else fails, Google it. There is nothing worse than getting a flat tire on a two way highway with no shoulder as semis are wizzing past in 20 degree weather and the middle of a snow storm.
Which brings me to my next point....
Snow chains or traction tires. They aren't always needed but weather can change fast in the winter. You may get lucky and not need them, but why risk it if you don't need to?
Hand Sanitizer. Your hands are going to get dirty. Pumping gas, filling tires, fiddling with your hood or trunk that have dirt and bugs now splattered on them, and also sketchy rest areas either with or without soap-yeah. Ew. Keep clean with hand sanitizer. Especially if you're planning on eating any of that road trip food.
Which by the way, perhaps you should pick up antacids and pepto bismol just in case. Fast food and potential food poisoning from podunk restaurants outside of Reno can be hazardous to your health. Take precautions.
Having an ample supply of music is a MUST! Get a stereo that allows you to plug in an iPod, MP3 player or even cell phone with music. If you don't have that kind of stereo, buy an adapter. This is not negotiable. Having just the radio to listen to is a PAIN when the signal gets out of range and you have to put your search button on overdrive finding a new station that you can stomach. Seriously, go with a huge stack of CDs over the stereo. Just make sure they aren't scratched as all get out and skip on you every two seconds.
My recommendation for good road trip music is stuff you can sing to and keep you dancing. You don't want anything that will make you drowsy on your drive. Classic 80s and 90s music will do. Get a little NSync up in here and everyone is having a good time.
There are a few great apps you can download on your phone that I've found to be helpful, they are:
Gas Buddy. I use this even when I'm home. Basically, it finds gas stations near you and gives you the prices as well as directions on how to get there. So you may be driving an extra mile to a different station, but you're saving money because it's 10¢ a gallon cheaper.
Trip Advisor. This helps you find hotels, restaurants, things to do, flights, and other things near by.
Yelp is pretty good in finding restaurants and things nearby and you can see how good they are... or not.
Weather Tripper (when it works and isn't freezing) is great for showing you upcoming weather conditions along your route. It gives you up to 3 days in advance.
Waze is another one I use even when home. This app let's you know about traffic, road hazards (ginormous boxes blocking the middle lane, snow and ice, or just a car pulled onto the shoulder). It even let's you know where some hidden cops are so you don't get that dreaded out of state speeding ticket.
LDS Temples is a great app for finding the nearest temple along your route, if you're into seeing such a thing.
Sudoku is a fabulous app to kill time and an internet or data connection is not needed.
Jewel Star is another fun app that doesn't need service to play on and helps you get addicted and not realize you've driven 6 hours across 3 state lines.
Tips for the road
Don't forget that your car is your means of travel. Make sure your tires and brakes are good as well as your oil changed, windshield washer fluid and all other fluids filled and fixed before you go.
If you have any rock chips or cracks in your windsheild, get them filled and fixed. Temperature changes can really make those spread and crack quick. If you get a chip on the road, wash it off, and put a piece of scotch tape over it so dirt can't get in and vibrate the hole to a large problem before you're able to get it fixed.
Check your trunk for a spare tire, a jack and tire iron for the possibility of a tire change. Also make sure your spare has air in it. It does you no good if the spare is flat too.
Check your tires air pressure before you go and regularly along the route. Don't forget your handheld gauge! (Mine has an emergency window breaker and seat belt cutter built in to it.) From experience, the "Free Air" compressors don't work half as good as the 75¢ ones.
Keep jumper cables in your trunk for a battery boost, or just to get a good shock to wake you up when you get sleepy.
Don't forget about your transmission fluid. If your car is struggling getting up those hills or speeding up to pass those darn 3 trailer hitched semis, check the tranny fluid and fill it. Your car will be grateful.
Road Trips are fun. You don't want them to be a hassle. If you take the proper steps to prepare, then you don't have to worry breaking down and getting lost 100 miles from civilization, cold, alone, hungry, and having to pee.
Be safe my friends and go out and explore the world.
