Howdy! Nice ride, I've got the same setup, '03 7.3L RB50 w/Quigley 4X4, just swapped over from SMB manual low profile top to a CCV high profile top though. I also got our rig with low miles on it, granted that was ~8 years, 60,000 miles...and $XX,XXX ago.
Anyway, thought I'd chime in about your rear bumper, I've got the same there as well, Reunel, I personally wouldn't swap it for an Aluminess, especially just to put on a Baja box, I'm adding an aluminess box to our rig, just mounting it on reunel's swing away jerry can open rack, just cutting off the sides of the rack and having a support frame built to hold the box. For the record, I put on an aluminess front bumper, so nothing against them, they make good stuff, but their rear bumper is nowhere near as bomber as our Reunel, especially for towing, plus I think they look better.... Have a great time with it, see you out there sometime.