Once sold a WWII Norton motorcycle... and discovered after the auction ended that the buyer was in Holland. Oops. Should have switched to "US shipments only" for that one.
We constructed an elaborate crate and shipped it off through an international freight company. Not easy, but it worked. Had I been thinking, I would have recalled that many motorcycles arriving in the U.S. are imports, and they come in their own special, pre-made metal shipping frames.
Along that line of thought, perhaps you could consult with a furniture store to see how their freight arrives and ask their advice.
Sending antiques that are fragile through motor freight is not that expensive, but is problematic for insurance. Most freight companies will not insure against damage on antiques - too much opportunity for fraudulent claims. If it is VERY expensive, you can purchase a separate insurance policy to cover a one-time shipment through a local insurance agent. We had to do that for a 19th Century English naval cannon that we sold to a customer in Georgia. $5,000 cannon - policy cost about $400 to insure it. (They have a minimum price for which they will write a policy.)
Local pick-up may be your best option, but would limit sales. No 100% correct answer on that one. Good luck!!