Hello David,

I tour Europe currently on my USA plated Motorcycle, I looked at tons of options this past year when I was planning my tour, this is what I came up with,
If your trip is over a month Shipping your bike starts to become a cheaper route than renting, if you're planning around a month renting will be far easier.
I shipped with Stefan Knopf Tours by boat, he will ship a container from Orlando fl guarantee for arrival before May 1st, all said and done a 1 way is $1200.
I know he collects or can arrange collection of bikes from all over the USA to put into that container but I'm not sure of the extra cost. I rode my bike to him around January and he stored free of charge in Orlando while waiting for the container. Once arriving in Heidelberg he stores for a Month for free, I believe I was told it was 35Eur a month after that, but I was there to collect so I can't confirm.
Air Canada from my research is the only Air cargo available from North America so they corner the market on it, There are other boat companies for shipping that are cheaper, but you likely have to pay middleman for customs fees if you go that route. Knopf clears customs US and German with no extra cost and bike is ready for when you arrive. I highly recommend his transport if it fits your timetable. I believe for transport home he ships back a container in the fall around October, but I haven't verified that or the return cost since returning is not anywhere on my radar ATM.
There is an option out there where USA citizens who shipped their bikes to Europe like me but want to sell in Europe rather than return it, legally they are not able to sell it to a European but they can sell it to an American so there is a market to buy USA plated bikes already over there. Europe is closing most of the loopholes for Americans to buy European plated bikes, by the Insurance route, you can buy it but good luck getting insurance without an address there. Ireland and Croatia seem to be the only ones I know brokering that type of thing, but I hear its harder and harder to get around the Insurance gambit.
As for an American to insure a USA plated bike its fairly simple, People like Knopf in Germany, Durby in Croatia (Sorry if I spelled it wrong), Motocamp Bulgria, and I think someone in Ireland all offer types of 3rd party insurance packages, some even with nearly full coverage and theft protection if that's the kind of thing you do. I went with MotocycleExpress a USA based but a German Alliance policy because I wanted full year coverage, I liked their price, and policy coverage. I advise to contact those listed above to see their prices and coverages, I personally now have met Knopf and Motocamp both are very stand-up people, MotorcycleExpress also has been very pleasant to work with too, (I have NOT had to file a claim yet so who knows what my recommendation will be if that is to occur, (my Disclaimer)). Those three I know won't lead you astray their prices are just different. Talk to them and get the one you feel most comfortable with.

I hope that helps you some, I am a planner too, so I did the same as you back in 2020 once I realized I needed a new place to roam, so I know the pains.

RidingTheUnknown

Estonia allows non-residents to buy and register vehicles in their name, and insurance is pretty straightforward (I helped a non-EU person do that last summer).