Nune
Welcome to OAUSA!!!
My first 4WD was a 93 Chevy 2500 Suburban, with the 454 motor, and it served the family very well. During it's service, it survived endless miles of dirt washboard roads, all kinds of weather, more off road trails than I can count, and the beating that the family dished out. It lasted 10 years, and after putting over 250,000 hard miles on it, it was finally time to let another assume the inevitable avalanche of maintenance problems. GREAT vehicle!!!
To directly answer your question (suspension), I will confess that, as my first 4WD, I was mostly satisfied with the suspension, and with the addition of new torsion bar keys (Cognito, I think), I didn't want for more. As I recall, the 3/4 ton Sub came with very stout suspension which raised it more than the 1/2 ton versions. With a bit of cranking on the new torsion bar keys, I was able to fit larger BFG ATs, 285x17, which roughly translated to 33s.
There is one other mod that I would strongly recommend, and that is the the mechanism that activates the 4WD. There is an actuator in the front end that uses heat to engage the front axle (not one of their better ideas), and it has the predictable feature of failing at the worst time possible. I know, because after mine failed, we spent several hours digging and preparing the trail so I could make it back to civilization in 2WD. It's been too long to remember the company that made a manual engagement cable that cured this problem, but some research will help you find a cure.
Only one other suggestion. If you run a lot of accessories (Ham radios, refrigerators, compressors, etc.) you may want to consider a dual battery set-up. GM was kind enough to build in a location in the engine compartment where a second battery tray could be installed, and this location will accept a stock tray.
I have several shops in the South Bay that I can recommend which I have relied on for years for the kind of work you mention.
Good luck!!
The Sub In The Snow

- IMG_1170 (Large).JPG (154.29 KiB) Viewed 383 times

- IMG_1173 (Large).JPG (149.26 KiB) Viewed 380 times