What's your fuel tank plan? Are you ditching the factory tank and triangulating links or doing a 3 or 4 link with panhad bar? You've probably seen the tahoe/danali on pirate that was coilover'd front and rear (and recently rolled) but it looked well done and would be good to get ideas from.
On the "luxo-wheeler" theme, I've really enjoyed our '99 K2500 SAS as even with just the work truck package it's a decent interior and everything works and works well. Our '04 2500HD SAS takes that to a new level with a quiet interior that once again is kind of base level but really nice. I like being able to drive a long way somewhere, wheel the truck (or not) and drive it home comfortably. And it's hard to beat starting with a 6.0L/4L80 and 14FF rear in the truck already. The 261/263 T-case isn't terrible either. The simplicity of the older stuff is pretty awesome but so is talking to your wife on a road trip it turns out!