One of the things you can do to minimize weight in your trail tool kit is to eliminate wrench and socket sizes that Isuzu doesn't use. Here is my list of common sizes I have encountered wrenching on my Trooper:

27 mm
24
22
19
17
14
12
10
5/8" spark plug socket
8 mm allen wrench (Aisin hubs)

As you can see, there are a lot of sizes you probably won't need on the trail, at least not for your rig. So you can eliminate something like half the wrenches and sockets in your kit, and of course carry a crescent wrench or two just in case.

Of course, it is not quite as simple as that...for example, while a 27mm socket works fine for all needed applications (torsion bar adjustment and lower ball joint come to mind), in many other sizes wrenches will be needed in certain places due to clearance issues. So, you say, why not just haul a minimal set of wrenches in the above sizes? Sure, a box wrench is slow, but it will get the job done...

Well, not always. As I found out to my dismay when replacing a timing belt tensioner on my Trooper in a campground in Moab, having the right size (24mm) wrench did no good for the crank pulley bolt, I needed a deep well 24mm socket to get into the dished pulley to the bolt. So now I carry a 24mm wrench and a 24mm deep well socket.

Another little tool that comes in handy is a 14mm box wrench with the end of the box ground down a bit so the wrench can fit fully onto the driveshaft bolts, against the curve of the flange. Not all Isuzu driveshafts are the same, and neither are all wrenches, so I suggest trying the fit of your wrench on your rig's driveshafts before you actually need it on the trail.

Another little wrenching tool I carry is a very small pipe wrench. This baby can remove brake line fittings that your other wrenches (including flare nut wrenches) have already rounded off.

I also choose to carry gear wrenches for most of the above sizes. Although not absolutely necessary, I find they often fit where socket wrenches do not, and really speed up the wrenching. It is up to you if the cost and weight are worth it.