I would focus on the tools needed for common failures when four wheeling. I often see guys with massive tool sets in their Jeeps/UTV's, but nothing they need. An SAE set is useless in that Jeep, so focus on metric. Get a socket for your axle nut. Get a hammer, pry bar, snap ring pliers, combo wrenches, etc. Basically, you need tools that will allow you to limp off a trail if you blow an axle shaft, drive shaft, tie rod end, etc.
When I work on a new offroad toy, I write down every tool that I use. That list becomes my tool bag inventory. I don't carry complete sets of anything, just sizes I need. Be smart; don't carry a big 4 way lug wrench, instead carry a long handle flex ratchet and 19mm socket. Instead of linesman pliers, carry vise grips that can be used to pinch off damaged break lines. Make sure you have a 12pt if that's what your u-joint strap bolts are. The trail is a ****** place to find out your tools are inadequate.
True story; I was on a UTV trip in Baja and a guy ripped off a front A-arm on his RZR. He went to fix it and had a 18v 1/4" impact, a claw hammer, and a nail bar......but didn't have the right sockets/wrenches to remove the arm. Keep in mind a 13mm, 15mm, and 18mm will fix 95% of that vehicle. WTF did he have a bag of carpentry tools?
