It's pretty simple really.

You need some recovery gear. I forgot to mention a full sized shovel up on the roof rack. I use big tension springs to keep it secured. (Bungee cords sun rot and fail) Tow straps work when someone else is there to pull you out, otherwise you need a good jack and digging stuff. If nothing else, the U.S. Forest Service requires you to have a shovel for putting out fires.

Tire repair kit and a way to re-inflate a tire. (Compressor) Tires are pretty much 98% of what gets you down a trail, you can't keep going on a rim. Maybe on pavement, but not off-road very far. If you're deep into the wilderness, and carry one spare like most people do, you should be able to repair what's already mounted rather than switch to the spare and have no other backup.

The rest is for comfort. If you get stuck for a while, do you want to freeze? Go hungry? Or die (literally) of thirst? Or... break out the MRE's and bottled water and bivvy bag? You DO have a Spot Messenger don't you?!?

Mechanical tools are nice 'n' all, (And a good idea) but after 30+ years of 4-wheeling, I've noticed that no matter what you bring along, what needs fixed is something you don't have tools or parts for anyway. (Other than common stuff like a fan belt) The only way that idea really works is to be on a Jeep rally where there's enough stuff from all the rigs on the trail to have a better chance of having the something you might need. Hardcore Crawl people might even have a welder aboard, but for a single rig to pack all that's needed for breakage would exceed the Jeep's cargo capacity. JMHO.

Heck, even at the rally I just came from last weekend, one lost their steering pump. The pulley cracked and broke. Of course, the serpentine belt needs that pulley for everything else, so it got towed back to camp. And, that was a MAJORLY modified Crawl rig with 44'' tires. Like I say, no matter what gets packed along short of a duplicate Jeep behind you, something will fail that you can't fix. Better to have a tow strap and a buddy(s) along to get you back out.