My wife and I camped out in our Dodge Dart all over the US and Canada in the 70s. We each had one suitcase each, stored in the driver's and passenger's seat at night. The back seats folded forwards, and there was a partition that folded down between the back seats and the trunk. This made a passable "bed", which was made even more passable by the use of air-mattresses and sleeping bags.

We had a small-to-medium sized foodbag which also held a small cook-kit. We also had a medium sized cooler. Late in the afternoons we would roll into a campground somewhere and find a flat spot to park, hopefully near some kind of picnic table. We'd cook dinner in a quantity large enough to always have leftovers for lunch the next day, which we would seal up in foil and then heat on the manifold while we were driving down the road the next day. Breakfast was almost always cereal with fresh fruit. We pretty much could keep to a $10 per day budget using this system.

People would often drive up to us in the campgrounds and ask "Where's your tent?" to which we would reply with a nod to the Dart.