It sounds fun in theory but can you actually live in a car?
There are a number of reasons you might consider living out of your car for a prolonged period: you might be trying to do a road trip on a budget, or you could be visiting a friend/relative that doesn't have a couch for you to sleep on. You might also want in on that glamorous #vanlife you've been seeing so much about on Instagram. Whatever your reasons, there are a number of things you have to consider before you pack your belongings in your trunk and head out on the highway.
First of all, you should know that there are no laws preventing you from living in a car or an RV. Said vehicle needs to be registered to a person with a fixed address on his driver's license, but as long as you can get a P.O. box or a trusted friend with a fixed house you should be fine.
However, there are laws preventing you from parking anywhere. That dream of yours about living in a van down by the river? Unless you own a lot near said river, you could be charged with trespassing.
Of course, there are solutions to this: you can go to a campground and rent a plot for a while. Be warned though - they don't like it if you stay for extended period of times, so you may need to move between campgrounds.
Something else to consider: while nobody can fine you for living in your vehicle, some aspect of life - like, say, changing clothes - is a punishable offense if done in a public place. This means that if you have to switch your underwear, do it where nobody can see you. Same thing goes for public inebriation. If you had a drink before going to bed and the police find you sleeping in your car on the street, they are fully within their rights to arrest you.