I am thinking in buying a JR west all are pass, and in the last day i thought about going from Kanazawa to Tokyo. I checked routes in Navitime and it says that it cover part of the journey, but I have no idea if I can really use the pass and buy another ticket for the area not covered (as I won’t be able to validated it) or if I have to buy a separated ticket for all the journey?
I’m not sure how much travelling you are planning to do on the JR West Pass, but you might want to look at the Hokuriku Arch Pass, as it covers the Kanazawa - Tokyo route.
You can also compare the different regional passes here: