My wife and I are dipping our toes into the overlanding world and just purchased a 2004 LX470 with 202K on the odometer. I just replaced the mud tires with Falken Wildpeak A/T4/W tires. It was heavily modified by the previous owner.
TJM front...
I originally went with lift and torsion bars, with no diff drop. After two ripped CV boots, I installed the diff drop and haven't had any issue since. It's a great suspension.
With the details you provided, Bring a Trailer will most likely be a good bet. Original owner, records, garaged, Arizona, locked - these are all the things bidders go crazy for. Me included. 🤤