It is a lot of fun to get on the road and just live out of your suitcase for a while in the USA. This vacation is really easy and stress free. You'll be seeing world famous places like the Golden Gate Bridge in San Francisco, the Florida Keys south of Miami or the Statue of Liberty in New York, and will stay wherever you want on your own schedule. Be prepared for a lot of great impressions and many great pictures in a short period of time. My preference for this kind of vacation has always been the car, that allowed me to be most flexible while cruising through cities or finding a place to stay the night.
Here are a few tips to make the most of your road trip in the United States.

Optimize your driving time
Outlining a rough route is the first step of planning ahead, because time flies by real fast during a road trip. Google Maps will help you to check distances and get an idea of the total driving hours between your stops. Also try to avoid Rush Hour in the mornings and evenings, because getting stuck in traffic will be heavy on your mood and your precious vacation time is slowly slipping away. Heavy city traffic during the week is 7-9am and 4-6pm across the nation.

Take breaks
Your passengers need to enjoy the trip too, so plan to make stops every now and then. There are many rest areas in the United States no matter where you are and your passengers will surely appreciate it. There are less rest areas in the middle of nowhere of course, but even if there's no public rest area you could always stop at one of the many restaurant chains and use their bathroom. They usually don't mind. If you want to find out about the next available rest area, a good app is Rest Area Finder. To find restaurant bathrooms just use Google Maps.
Photo opportunities like gorgeous mountain views at the Blue Ridge Parkway, beaches in Clearwater, FL or out of the ordinary stuff are just some of the many attractions on your way, which are good excuses to stop and take a break. Stretch out your legs and take some awesome pictures.

Put your gadgets on the spot
Before the smart phone area I used to be pretty good with navigating through maps. Today, you basically just hop in your car and worry about where to go later. Smart phones and tablets make it very easy to find your destination. And if you don't have an internet connection on the road, there's always chains like Starbuck's or Subway, etc. who offer free wi-fi. There's also the opportunity to just stay in your car on their parking lot to pick up their wi-fi signal.
Not to mention mobile hotspots, which can be purchase from Virgin Mobile and other cell phone providers. All you need to do is pre-pay for a day or a month and have access to the internet wherever you are with your tablet or laptop. Even your phone can pick up the signal.

Nutrition on the road
While being on the road for hours you can't always find the perfect place to eat and your mood might change for the worse. Don't wait for the next restaurant to show up on the horizon. Pack some protein bars prior to your trip, so that you have a backup for between meals. There are however some really nasty ones on the market, but there are also really good bars, like Mojo Bar, No Opportunity Wasted Trail bars and NoGii Bars. The bars are low on calories, all natural and fill you up until your next warm meal. I hope you won't fall for one of the candy bars in gas station, because these just give you a sugar rush, followed by a sugar crash that'll just make you sleepy. And you can't afford to be sleepy on the road.

Where to stay the night?
You won't have a lot of problems finding a place to stay the night in the USA while being on the road. Plenty of motels with different price ranges are available for business nationwide. Reservations are usually not needed, because you'll always find a room. To save some money on the motel, find these free coupon booklets at gas stations or rest areas. Often stocked in one of these Newspaper boxes you can't miss it. The booklets are usually local and just for the state you're traveling in, but they offer a good selection of motels that are nearby. You'll likely save 10-20 dollars per night just by handing over the coupon at check-in.
With a common American roadside assistance program you're covered when your car breaks down. It also usually comes with benefits like discounts for entertainment and hotels, and most of all assistance when your car breaks down. Just mentioning the name of your membership will often shave of a few bucks off your bill.
The selection of motel chains is big, but over time I figured out my favorites, which are Comfort Inn, Best Western and Quality Inn. They are pricing their rooms fair and keep them clean. Some are called Inn & Suites with the difference that your room will be on the inside rather than the outside, which makes me always feel a little safer. I've also experienced older motels like Motel 6 or Econo Lodge and realized that you really get what you pay for.

Rental cars
Alamo and Thrifty are rental companies that I have made good experiences with. They'll cost you less and provide cars in good condition and with low mileage. There may be some money to be saved if you check the price from your home country. Sometimes you get better insurance coverage and even a better price. I learned that while shopping for an Alamo car, looking on website. In the end I booked through their new iPad app, which earned me an additional discount through a special promotion. Another factor to look out for is where to drop off the rental car when you're done. There may be significant savings by returning your car at the station where you picked it up. It varies by state though.