Mike, I guess what I take would be related to how far from civilization I was headed, why I was headed there and which truck was doing the towing.
If I were going to a show there's a lot to be said for booming the S-280 camper into a 6x6 like I did for Gilbert last year and hooking up an M105A2.
But, if I am living out of the trailer...
As somebody else already stated I wouldn't normally be carrying any breakdown stuff or fire extinguishers, first aid kits etc in the trailer since that is always in/on the truck. For the M105 I would only have a spare tire if I was towing with a 5-ton since our deuces have 5 spares on the truck (the one under the bed and the four outer duallys). For the M101s we have one of the tire hangers that hangs over the tongue.
If I'm going to be doing all the cooking/baking for full meals we have a chuck box for staples and a cook box with detachable legs that holds a camp stove, lantern and all the cooking/cleaning stuff for 5-6 people along with plates, cups, spices etc. Add in a camp style Dutch oven if the amount of time spent in camp allows for baking or roasting. I often bring a Weber kettle grill grilling/BBQing, either a big one or a little Smokey Joe. It doubles as a fire ring in areas where you can't have a fire on the ground.
For short trips or if the weather promises to be rough I bring frozen vacuum packed pre-cooked food and just heat it in hot water. I generally only pack cook gear to match my intended menu so some of the stuff listed gets left behind based on that. Chairs, table, coolers, water and fuel cans etc as needed and a carpet strip for the floor.
Add an electric lantern with rechargeable batteries and charger if needed. We have 12 volt and 24 volt inverters and take whatever is needed for our power needs. Same with 28 volt ration/hot water heaters, propane or liquid fueled lanterns, propane stalk and manifold yadda, yadda, yadda as needed. I rarely carry a generator unless I’m going to be gone for more than a week with no prospect of getting fresh ice.
I'm OK with a cot and mat or just toss a bivy sack on the ground but have also been known to take a queen sized inflatable mattress. Sometimes (rarely anymore) I bring a tent.
I usually tote a 12x16' canvas fly and poles. I may break down and get one of the commercial shelters with side curtains though.
The pioneer tools cover most camp work but for serious off roading I have been known to carry a couple of saws and peavys for moving logs. Generally this would be a small limbing saw and a big felling one.
When appropriate I take a weather warning radio, up to date topo maps, waterproof map case and a good orienteering compass.
In bear county I carry a bear bag for hanging food and anything else that will attract bears (toothpaste, soap and other hygiene items are bear magnets, too) and when legal carry a rifle. I don’t mind bears being in the camp with me much but most black bear attacks are predatory and I feel better when I have a rifle at arms reach.
Lastly, when in the boonies I leave a copy of my planned route and schedule with someone I trust and stick to it.
I have the tall walk-in height cap off my old M1008 and it is within a inch or two of fitting an M101 bed. I have a extra M101A2 in great shape and am considering mount the cap on permanently. We'll see how that plays out. I'd have to cut off the lugs the tailgate pins and chain pins go through so it will not be easy to reverse and I'm still mulling it over.
I'm also looking for an M1061 or similar trailer for the S-280. If I can get a clean trailer like indfy4x4abs it would become my primary show hooch and cargo trailer behind the M915A1.
Lance