How does the priority go for being outdoors?

Are you planning on going without one?  Take a shelter (tent/tarp/etc.).  Take food.  Take insulation (sleeping pad & bag).  Take a water filter.  You should always have all of those before you go.  If you go camping without them, you either need to know what you're doing, or don't go.

You can go a week or more without food before you get dangerously sick.

After a couple days without water, you get dangerously sick.

Just one night without adequate shelter/clothing an you're dead as a mackerel. 

Water, Toilet paper and weed.

Water, food, shelter. You can survive longer without food than water.

If you are just going out for a day. its just water and food. If you are going out in the woods overnight. than shelter firewood, food and water.

Which priority are you referring to? Is this something you read about, somewhere? Are you referring to wilderness activities? Also, why is your question in the Singles and Dating section?