I've been a general and repair contractor for 45 years. Other than some specialized tools for plumbing, flooring, plastering and concrete, etc., I find that the number of mechanic's tools needed can be limited to one of those sets in a blow molded box plus a few big wrenches, pliers and screwdrivers.
So many tools are crossovers that you if you have those basics you are prepared for many tasks, even plumbing and electrical. Some of the necessary tools for any repair/service truck that is not just a truck for mechanical repair:
- Drill motor, whatever your choice is
- Circular saw with a wide variety of blades
- Sawzall and jigsaw
- Vacuum
- Multi oscillating tool and a variety of blades
- Angle grinder with a variety of discs
- Sander, preferably some kind of shaker and a belt sander
- Extension cords and a small amount of electrical gear like tester and wire fittings.
- A small air compressor with enough capacity for short bursts on a bigger tool
Options include a chop saw with a variety of blades, nail guns, router with accessories
Now that having been listed, I have two Bucket Bosses full of hand tools, too many to list, another full of drill/driver bits and accessories, plus screws of many kinds and anchors. I have another box full of small carpentry tools plus files, stones, clamps, staplers and on and on. Then there's the box full nails and every other piece of hardware you will need on a typical day. I typically carry at least a couple of paint brushes and some filler materials along with a mud pan with some putty knives should I have to pick up some patching material. Maybe some spray cans of whatever, too. You can always use some WD40 and a bottle of glue.
But when it comes to end wrenches and sockets I have always gotten by with the kit plus a set of 3/4 drive and a couple of big adjustable wrenches. Whether it's a bolt on the patio cover or a 1 inch lug nut, I've got a tool.
However, I work on homes and offices, not Peterbuilts.