If you can find a large tree to climb up in and sleep in the branchs or a kids tree fort, the attic of an abandoned house but you would have to clear the house first , the hay loft of a barn the top of a grain elavator the roof of a warehouse or store , the only problem you might face is a large group of zombies gathering around your temporary shelter you will have to make your way through upon waking.
I would suggest that one goes for protection above most other considerations. If you're just lodging for the night, then food shouldn't be too much of a consideration if you prepared beforehand for the trek, and water shouldn't be too hard to find. Stealth is easy: just make sure they can't see you, hear you, or smell you. So just stay out of sight, don't have a screaming contest with your best bud, and for the love of Christ, don't open a window! This is vital! Your friend may have the most disgusting farts on Earth, but it sure beats having a ghoul chew out your brain.
Me personaly dont think cars would make a very good choice to sleep in and it dont matter how well you secure it. All it takes is a group of stenches to surround the car and flip it than your screwed. If your using a veichel with some weight you might be ok, but I would rather find a vaccent building and make it safe house for the evening but thats just my oppion very ones is gonna be different and some will agree with others
yeah i will be staying far away from cars and going strictly on foot. silence will be your strongest weapon here. a temporary shelter i would use is the roof of someplace that isn't too high up. high enough to keep zeds away but not too high i cant jump off somewhere if surrounded by some zeds in the am. tuck and roll to avoid breaking or spraining anything, but still a fast limper will be faster then the fastest zed.