Short answer: It depends.
There is never one “best way” to travel. It all depends on where you want to go, how long you have and on your personal preferences. Here are some things to consider while you’re planning long-term travel in the US and trying to decide how to get around.
Note: For the purposes of this article I consider “travel by car” to involve sleeping in your vehicle for the majority of the trip. There’s a lot of resources about it on the web, (my website is A Year in a Car.) Try searching for vandwelling, car living, or urban camping.
If you’re interested in a trip that hops from one city to another, public transportation between the cities is going to be easy and driving between them is going to be long and boring. (Though there’s nothing like driving all day to put the map into perspective.) Yes, even Los Angeles, the birthplace of car culture, has good public transportation. Driving around an unknown city and getting lost or stuck in rush hour will definitely cut down on the fun of the trip. Traveling between cities is much more fun if you don’t have to do the driving.
While public transportation in and between cities is easy in the US, most of the country isn’t urban. Travel by car will be the easier option if you’re visiting Carlbad Caverns in New Mexico, Point Reyes in California, Zion or Bryce National Parks in Utah, or any of the other approximately fifty million other cool spots in the US. If you have two or more people to share the driving that’s even better. You can split the cost of gas and pay for your own tickets.
Traveling by car also means you don’t need to plan ahead so much. You have no timetables to keep track of. If your car is your hotel there are no reservations to make. You can stay easily stay longer in a place if you like it or leave earlier if find you don’t.
Assuming you use your car as your accommodation, travel by car is significantly cheaper. The cost of gas may be more than the cost of public transportation but cutting the cost of hostels and hotels out of the equation more than makes up for it. Traveling by car also makes it easier to adjust your spending to fit your budget. Your main fixed costs become gas and food, both of which can be easily cut by staying put exploring an area more deeply. Get a campstove and buy more food at grocery stores than at restaurants.
The social scene
For ease of meeting people, backpacking and hostels has got vandwelling beat, hands down. Not that it’s not easy to meet people while living in a vehicle, but while staying in hostels it’s practically forced upon you. If you’re a shy person hostels are a great way to break out of your shell. If you prefer being able to easily have alone-time then a car is great. For more tips on meeting people outside of hostels while traveling check out this previous ITP Article.
Safety and comfort
After two years of living on the road I’ll fully defend the idea that living in a car is just as safe (if not more so) than backpacking, for both your own personal safety and your property.
Personally, I prefer sleeping in my own bed each night. I like not being bothered by someone snoring or stumbling into the room at 3am. The car can sometimes feel like tight quarters, but they’re my quarters and I don’t have to share with anyone.
There is something very elegant about living out of a backpack. It’s a nod to simplicity to know that everything you need you can carry in your best backpack. But if you want to be lazy about the planning, if you want to carry enough food and water so that you can randomly boondock in the woods for a week, or if you’re a voracious reader, photographer, obsessive crafter it’s nice to have the extra space for luxury items.
What works best for you is going to depend on your situation and the kind of trip you want to take. If you live in Los Angeles and want to spend one month in Boston driving there is not a good idea. But if you live in Los Angeles and have a month to travel around northern California then taking a car is your best bet.
I highly recommend trying out both on short trips (or better yet, try both on long trips). There is no “right” way to travel and the only wrong way to travel is not to do it.