JamesDowning wrote: For instance, if you destroy a front CV shaft, just remove it and continue. At least you'll be able to drive using the rear axle.
Hehe. And if you grenade your rear end, the front wheels can get you 20 miles back to pavement.
My worst trail failure was a tie rod end. Could barely get to the side of the trail, and my spare was AT HOME! Teebes had to drive 60-70 miles to Fresno to get a spare for me.
A megafuse will only kill some of the lights and the entertainment systems, but the truck can still start and run. That's not fatal, but it's worth carrying a spare. Many other fuses can disable the engine, so it's definitely worth carrying a set of all fuses and relays, plus schematics.
I could put together a PDF schematic package if that's interesting to people who don't have the factory manual.
A SPOT beacon can do wonders for girlfriend or spousal reassurance.
http://www.findmespot.com/en/A lot depends on your budget, and how much your girlfriend ALREADY knows about your personality and tolerance for risk.
As to what fails most often that can prevent you from getting back to pavement - it's definitely tires. I've put in three plugs on one run - if all I was carrying was one spare tire, I would have had to abandon the run after the first puncture. So get a good plug kit such as one from ARB, not the $4 cheapies, and a good compressor.