I've published 6 books so far on KDP, and I'm based out of Calgary. When I log into kdp.amazon.ca, it actually redirects me to kdp.amazon.com. It's one and the same site.
I think what you're looking for firstly, is what marketplaces your KDP account is configured for. After you log into KDP, click on upper right-hand link for your account, mine says "Adam's Account."
This will bring you to a screen that has your address, and if you scroll down, you will a spot called Tax Information (make sure you've got a green checkmark there, if not, you have some work to do). After that is Amazon Marketplaces, that's where you'll see how you are going to get paid for each of the different marketplaces.
For my account, every marketplace states either EFT or cheque.
When I go to publish a title (and I just setup #7 today for pre-order), I just setup the information, upload the content, and set the price in all the various marketplaces. That's all I need to do. Amazon will publish my books from there.
People who want to buy your book will be required to go to the location associated with their account. For example, when I'm in Amazon.com looking at an eBook, I can't buy it. There's a link over on the right hand side which will take me to the equivalent page on the Amazon.ca site, which will then allow me to buy the book.
So there's no "publishing it on KDP US vs not," there is only publishing it. Everything else seems to be driven from how your account is configured.
I hope this helped,