This is usually how I run my trips whether I am alone or with others. If others are planning to go along I supply a detailed list of what I expect them to have packed. I have found that others (especially inexperienced folks) fall short every time and even though I prepare for it, I try not to cut my own needs short. So everyone is expected to be responsible.
I. Security
Includes finding the safest location for people, gear, and vehicle. I avoid locations that have deadfall/widow-makers, flash flood areas (observe the bank lines of waterways for the highest water marks and debris hung up in trees). I also look for insect nests, whether on or in the ground and in trees (bees, ants, etc.), and snake holes. If in an area that homes dangerous animals, I look for animal runs, tracks, droppings, etc. Depending on location and isolation, I may also rig a perimeter alarm system. Weapons of choice are included. The worse trip is one spent in fear.
II. Gear
This stage of unloading gear is dependent on weather conditions. If it's pouring down or snowing, I utilize a tarp extension that covers over my tailgate area so I keep supplies and ME a bit drier as I set up camp. I have gear packed in reverse order of that which needs to come out first.
III. Shelter
In the most inclement weather I may choose different sheltering systems. I may stay in the back of the truck under the cap, or in a tent, or right out on the ground. Regardless, I always have a tarped area for the occasional shower or flurry, not to mention a sun shade. Part of my shelter system includes the proper clothing and footwear. As in seasonal camping we all carry sleep systems but I always have a military sleep system packed in my rig for that never know when situation. Hypothermia is a real threat even in warmer temperatures. It includes a Gortex Bivy, a snap in sleeping bag, and comforter, a wool blanket, and Thermarest self-inflating air mattress. Underneath that is a foam ground pad for added cold ground protection.
IV. Fire
Regardless of the weather, I try to get a steady fire going as quick as possible. I carry clean fire wood and tinder along from home to get a fire going when I arrive in camp. It is definitely an added security bonus. If while gathering additional fire materials you become cold and wet, it is a bonus to come back to a nice fire right away. Not to mention having a little kettle of water heating up for a brew asap. (Need I mention a fire must be supervised by someone at all times. If alone one has to determine the order and necessity.)
V. Water
I never travel anywhere, not even to he grocery store, without some supply of water in my rig that will extend my life (and others) at least by three days. Not in today's world. So I begin with a supply of water and know where I can get water at any given time. Topographic maps are wonderful for displaying all water resources and I keep paper topo maps in my truck always.
VI. Food
When all is said and done, a good hot nourishing meal before bed is an absolute must. I also highly recommend drinking tons of water, especially whenever you eat. I keep a few snacks on my person always for moments when I just can't prep a full meal, or when the energy levels start dropping. Especially in very cold weather.
The order of things are subject to weather and helping hands that come along, but this is based on my needs when alone on or off road.