Welcome Dustin,
I'm new here also. I just picked up a 2006 Tahoe LT, 103k miles, 2WD, 5.3L, ZW7 suspension RPO so we are in a similar boat. I translated the RPO codes found in my glove box, changed oil, belts, partial steering/brake boosting fluid (need to do more flushing ran out of fluid), brake fluid (need to find out more on flushing all there also). I have the knocking sound/feel in the steering and odd acting shocks. I have a new set of shocks on order including Nivomat $218/ea. The parking brakes don't work, I pulled one rear brake drum off to look around. So as you can see I'm slowly working over the car checking and replacing things as I go.