I was talking with a coworker and he claimed that the Japanese planned on invading the west coast eventually specifically by using the Aleutian Islands as a base and coming down the coastline through Canada from there. From what I understand the Japanese hoped the USA would sue for a quick peace after Pearl Harbor and when that didn't happen basically just fought a defensive war with no real hope of seriously harming the US homeland. Now I know there was fighting on the Aleutians but was the invasion of the USA really the end goal of the Japanese fighting there?
No not one bit.
It was in short laughably beyond their capacity to support and sustain. Yamamoto harbored dreams of taking Samoa, Hawaii, and Johnson Island and such to push the USN back to the West Coast. But most of the IJN saw this was at best a fever dream, it was a major concern that if Midway went forward that was the next step.
Nor is it a sure thing that the IJN could have gotten a large enough force to California or Canada. Just getting the Kido Butai to Hawaii was a near run thing, taking most available fueling assets, and Midway took even more of it, just to move the battle fleet and a Regiment sized landing force. While plans to land a few divisions on Hawaii are questionably beyond their capacity.
On the larger question though is that such a nice doesn't help the IJN. Every support ship taken away from the Southern Resource Area is a hit to the flow of fuel and rubber and steel to keep fighting.
Shattered Sword give good treatment so does Combined Fleet.com, and Ian W. Tolls Pacific Crucible.
The Aleutians were essentially a side show to make the IJN feel better and try to block lend lease flow, and possibly forestall a counter attack in the North Pacific. There was minimal interest in pushing the advance there.