I been meaning to reply to this thread... I have slept in two different cars for varied lengths in time. Both are less then ideal, yet a rewarding experience. You will need to be organized, clean, and stealthy. I do advise keeping a gun in the car, but I am bit a anal (had a few crack heads made me nervous). I do advise on preparing and finding a 24/7 Gym (also a place to masturbate).
93 Chevy Corvette 2.5 Months, until I sold the car:
I lived with my parents, but there crappy marriage and them finding out about my sexuality pretty much forced me to go. I had a good size investment account at this time nearly $30,000. I did not not want to touch this money at all. But I only had $2,900 in checking/savings. I had to get a storage unit to put my 63 Ford Falcon Convertible (Fathers car, did sell after a while) and other belongings. I always paid auto insurance in full and really only had cell phone... I did not have a job and spent my days looking.
But at first I slept at rest stops off I4. I did this for a while (4 Days), but this is also illegal to overnight park; go figure and cops do patrol! I was harassed a bit, but in the end just moved along. I then started sleeping in the dark corner at local Wal-Marts. I had 5 different stores I would go to, I would do it in random. This seem to be find and no one seemed to care. Sleeping was not the best and took 1-2 hours to fall asleep. Depression, thoughts of suicide, and anger was running though my head. The best I could do and was a lot more comfortable then you would think. Was move the passenger seat forward and laying the back rest toward the windshield. I would then lay my feet on the seat back, my head in the hatch area. I had a blanket and use the cargo cover for a since of privacy. Tinted windows and sunshade for the windshield helped allot. But this Vette was bright yellow and the windows fogging up probably bought a lot of attention.
Organization is the key. I would go to storage every 3-4 days. I had 3 small bags, sleeping bag, pillow, handgun case, first aid, two pair of shoes, and covered everything with the blanket during the day. The 3 bags was pretty simple, (1) clean clothes with hygiene gear, (2) dirty clothes, and (3) food. Food was mostly beef jerky, canned fruit, peanut butter and bread... I lost a lot of weight, but looked healthy as I spent a lot of time in the gym.
There is so many different local laws and difficult in knowing them. Its not illegal to my knowledge to live in your car. But there's so much BS that a cop can make your night a living hell he can book you with... Also homeless shelters, they want you to attend AA/Drug meetings during the day for every night you want to sleep. They don't care if your clean, they just ask,"Then why are you homeless?" Just remember America does not welcome the frugal, so don't be an eyesore.
I did get a job after a while, best job I ever had. It was in aviation doing commission sales for an interior restoration company... Made good money, but they went under.
72 Triumph Spitfire, 6 days:
Not really much can be said, I was in between apartments. I moved out of one and could not move into the current one till a week later. So I went on a road trip/adventure. Did the same as above, but was scared utterly shitles. I could not get comfortable and was afraid some crack head would come by with a knife...
I hope it helps, I mostly just typed out what immediately came to my head. But feel free to ask some questions. All in all, I am considering doing this in the near feature. All the way until I complete college. It is a thought that seriously been running through my head. Mostly because I want to save money and move to New York City or San Fransico after college. I also don't have much family. Dad killed himself in front of mother, mother has severe problems due to it. So leaving family behind entirely, does not seem like a bad idea; seems relieving.
Anyways if I do it again it will be with a van. I will probably cheap out and buy a conversion van... But I been thinking about buying a nice cargo van, a long one such as a Dodge Van 3500. I have scaled drawing of a nice set up. Would have a nice wood interior similar to a log cabin with private sleep area in the back. But the center would be an office with fridge and and microwave. I would line the roof with solar panels and have a nice spot for batteries. But I am unsure if this is possible, at least in the $12,000 range. I don't want an RV as I can't drive it to class or blend in...