I like the suggestion, but had to do a bit of research for it.

As with sailing, traveling routes are not as simple as with flying.

So I began to wonder how common it would've been to sail from Japan to the US during that time. Which is why I did my route as I did. The Atlantic was more common to use, at least during a certain part of history.

Here's the common route too Australia

But, I ended reading that whole reply more or less. https://www.quora.com/During-the-age-of-sail-how-would-crossing-the-Pacific-Ocean-have-compared-to-crossing-the-Atlantic-Ocean

And I guess yours is plausible and might make for a better story, actually. But pretty much just barely timing wise, as the scenario takes place in the 1860's right? The Treaty of Kanagawa was signed on March 31, 1854, ending Japan's 220-year-old policy of national seclusion (sakoku).