Buying a bike advice needed

[Dezmo]

I come to Thailand 2-3 times a year, and work remote (a few months at a time) and now have the retirement O ME visa to get in easier :)

I like to ride big motorcyles and tour. I have a USA license and IDP. I want to get a bike here to do some touring, and keep it with my friends home near Bangkok when not here. .. but we spend time in Hua Hin.  I am looking for a used (few years old) Honda Africa Twin, Transalp or BMW F860 GS.   So a few questions... and advice needed:

- Might it be easier to get a bike from a dealer so they can handle registration, insurance, etc?  

- Are dealer negotible with price or it just depends? I have a Thai bank account so payment is not an issue

- Does insurance  and registration usually come along with the bike, and/or how do I renew I assume after a year?

- I assume I may need an updated TM30 (I have a close friend here so not an issue).

-  Would I need a Thai license?    Currently I have a USA license but also got the 1-year International permit.  I have heard of some insurance companies refered to - but assume personal injury is limited and I should (and may) just get health insurance here since dealing with USA insurance is a hassle and may be limited.   

- Anything I am missing?

Thanks...

[Mazz11]

I plan to do the same in the future so any advice coming your way would be appreciated by myself also.