>>54847501Alola is explicitly said to be extremely far from Kanto, just like Hawaii is from Kanto, Japan. And every time you move from a region to another in SV you have to take a plane so no, Kitakami isn't "accessible" from Paldea and Unova, not more accessible than any other region with an airport at least.
Kitakami is also based on irl Kitakami and the region around it btw, it's obviously south of Sinnoh, Perrin's quest even explains you the Ursaluna you find there came swimming from Sinnoh long ago.