Talk of boxing these up makes me nervous... they are valuable enough to be worth TRULY professional packing, including a proper sequence of shock-absorption materials inside of custom-made wooden crates. I wouldn't trust those in cardboard, period. I MIGHT pack them very well into professional aluminum gear crates, like roadies use with pro gear on the road, but I'd probably add further protection, even then. I'd use "extreme overkill" in the packing of these (unlike most other gear, which just needs "overkill") and I'd buy AMPLE insurance. Of course, the tubes would have to be removed and packed separately; vibration can make tubes become microphonic.
The safest way to ship these is to box them up well, and sit them on your lap in a chauffered and police-escorted Humvee, with their own seatbelt as well.
EDIT: NOW I see what you have in mind; local transport. Okay...
As for accessories, anything ORIGINAL that you can add to these, would tend to increase their resale value. That includes owner's manual, service manual, original brochures or ads, original packaging, etc... Whether you get your money back on such purchases depends on how much you pay for them, but usually assembling all the stuff together is worth the investment.
You've made all of us dream a little more, and given us all the hope that one day, we, too, might get so lucky. Thanks for the reminder that "Miracles do happen!"