I bought a boat in TX and registered it with a birth certificate and driver license, I am canadain and had no problems with it at all. They even said I was allowed to keep the TX registration numbers as well, and advised that If I went back to canada with the boat that I transfer registration to Canadian and did so with a 35.00 transfer fee three years later.
What ever state you reside in the most will collect your taxes, As for the loan, as long as you can verify your employment and have a printout from your bank statements of the last 6 months or so they will see your spending patteren and if good then you have the loan.
As to where you keep her, thats between you and your insurance, some are different from others and have requirements that you have to meet to decide what and how your insured.
Now that your in the fold welcome and coffee is on you next time...