I'm gonna start with airbags...as I feel there's too much squat out back when the trailer is hooked up...
I had a chance to crawl under the truck the other day... Shook the various bits of the driveshaft as much as possible... The carrier moved a little (maybe 1/4 - 1/2 inch) as I pushed and yanked... U-joints look good(no movement or rust evident) so I'm keeping my fingers crossed that it's the pinion angle that's making such a ruckus....
Maybe I'll start putting some coin in the piggy bank ... Saving up for a new one-piece replacement in the future...