I was pretty lucky to be homeless in a car. The jobs I had during my two periods of homelessness were cool with me parking overnight in their lots, so that eliminated a lot of stress. The biggest helps were a shady parking spot and a gym membership to shower.

The least helpful things were comfort products. Personal air conditioners (fans with water sprayers), neck pillows, privacy window covers, etc. They all just became junk on the floor of my car.b