QFT!You need to know your truck. The easiest way is to build it yourself.
I do suspension myself. You absolutely should do most of this yourself, as this is a tricky area. I allow good tuners to give me a custom shock valving. If it's not quite right, I'll retune the shocks myself by tuning the shim stacks.
Tires, brakes, rotations are done myself. I drop my wheels off loose.
Batteries, lights, winches, alternator, and starters are all done myself.
Axles, I go to a known good axle guy for gears and lockers.
Steering box, pitman arm, power steering pump, are all components you need to understand.
If you can't do it yourself, I'd limit my travel to reflect such. Don't go places where your suspension is going to fail, or the trucks has a risk of under body damage.
Also get an engine creeper, those weird ladder creeper things that allow you to lay down OVER your engine. Every single part in your engine bay requires hands on attention. Easiest way to to organize that? Hand clean every single checked part. If it's dirty, service it. They don't hand polish the bottom of race cars between races to keep them pretty.
I am getting into building my own axles now. I have a D30 project sitting on a couple of sawhorses right now. Plans call for truss, gussets and an Ox Locker.
It is getting to the point that about the only things I don't do are AC service, automatic transmissions, injection pump service (diesel) and the machining required in order to rebuild an engine.
For me, that is working out to be as close to a sweet spot as I can hope to get. Those are generally services that are performed by more skilled technicians. That helps me keep my distance from the numbskulls for whom I have no patience.
I am totally with you on the tires. Those shops are some of the worst. They don't touch anything more than I can help. Just dropping off the wheels and picking them up later has made a substantial improvement in my quality of life. Damaged rims, stripped lugs, tires mounted backwards... I think I have experienced just about every failure mode they have to offer, short of them driving my car into a wall. I am very much done with folks of that skill level.