Ah, I see. Judging from the last part of the chapter, we're a least half-way through the planned duration of the manga, and it's going to end when Mr Smith takes all his photos by retracing his journey back where it all began.
I'd say it's pretty obvious and the time is right: 82 chapters for a monthly series is already a lot, and ~120-160 would be quite a lot.
As an aside, I remember that it took me quite a while to realize that Henry Smith is the actual MC of this manga, not Karluk and Amir. That's why we always fallow his journey. I mean, we're used to it now, but I remember people, and myself, being confused and peeved as to "Why are we following Henry so long; get us back to out married couple MCs".
Actually, I'd argue that the whole story is an adaptation of his journals.
Anyway, great chapter as always. This work is so unique and a result of such obvious hard work, that over the years I just came to consider it one of the best manga I've seen. That's why the thought of it's inevitable end is so saddening to me. But well, maybe her next work will be even greater. Something like ancient Roma or Greece, that's be even more dope.