I travel the southeast for my work. I may be 300 to 400 miles from home at any given time. I also hike the Appalachian trail quite often. This gives me a pretty good ides what it takes to survive for a few days or even a couple of weeks. What I always carry in my vehicle.
A very good back pack (no cheap piece of crap)
Water purifier ( mine is a pump type )
Alcohol Stove ( mine is made out of a aluminum can)
Denatured alcohol (for stove fuel)
four flash lights ( 2 head lamps and two hand held )
lighters,matches and fire starter. ( I use Vaseline soaked cotton balls)
4 days of freeze dried food,snack bars ( I could stretch this out for 8 days if I had to )
Firearm/ extra ammo
Titanium cook pot (weighs 3oz)
rain gear (poncho)
Extra warm clothes in the winter
sun screen,bug spray
first aid kit, hiking boots and socks
I always have a case of water in my vehicle.
I'm sure there are of few other things thrown in there, Can't remember it all. My pack weighs around 30 lbs without water. I figure this will get me close to home are at least to some one I knows house.