The easiest way to approach this issue is to just to have someone you trust arrange to purchase a bike for you in the location where you want to start.
You can have them walk into a dealership where you have pre-arranged the purchase of the bike with the dealer. Send the full payment to the dealer who will only use the local person for the address, title, insurance, and taxes. Think of it like a gift purchase.
Every state should title and license the bike in both your names. The paperwork, depending on the state, can take a couple days to a few weeks. Arrange to start your trip AFTER all the paperwork has arrived for the bike. Once you arrive, have your contact take the bike off their insurance and move it to your international insurance. Really, the only reason you even need insurance is for your liability should you hit someone. Comprehensive insurance isn't necessary unless you want to get compensated should you wreck the bike. Any injuries you might incur if you have a crash will be covered by UK NHS.
Prior to departing on your trip. Prepare a bill of sale for the bike with your contact and have your contact sign the title when you arrive. When you get to your end destination, sell the bike.
On a driver's license, review this:
https://www.usa.gov/visitors-driving
An IDP is super easy to get and your UK DL is not a big issue for most places. If you show a passport, a valid UK license + the IDP, you are legal. Just observe the laws and you'll be good.
The only hitch here is finding someone you trust to set this up and being able to sell the bike when you leave. If you are willing to take a loss on your purchase, you can move the bike at most dealers. They will cut you a check on the spot. However, with a little arrangement, you may be able to pre-sell the bike.