Beat all 15 other gyms, Fight your rival in Mt. Moon and Talk to Blue/Green on Cinnabar island.
The last Kanto gym is in Varidian City.
Blue, the last gym leader in kanto region
Blackthorn if you are including Kanto its Viridian Pokegamer01
There is no 'last city' because you can find any of the Kanto Region cities in practically any order.
It is to the east of Johto, west of Kanto
in the kanto
you have to beat jotho then kanto
kanto ,joto
yes you can
Latios
In kanto
No, only jhoto and kanto