I have investigated all. Yes, the Swivel Wheel will do the job BUT it is mounted via bolted to a modified frame. You most certainly will void all warranty. Second, you may find yourself parked in the emergency lane on a bz highway as the state police refuse to allow you to go any farther as a tandem tow. There are horror stories out there!
Solution: as suggested, approved alternatives including a motor home.
OR, just rent a bike from Eagle Rider at most places in the US for $200 a day or $900 a week and give it back! Best choice since these bikes are mechanically excellent and current year models. They have unlimited miles. Dollar to risk, there is your best deal!
Last year for our final Daytona Bike Week, had the wife tow our 2 big bikes on our dual hauler following me. It's almost impossible to rent a bike during Bike Week or Sturgis. Have rented many times in Las Vegas HD and rode to Hoover Dam and beyond! Rented in California and rode Highway 1 north from LA. Beautiful memories.
I have been riding 55 years and wife has a 1700cc cruiser and has been solo for 21 years!
Make wise choices! Rubber side down!