I think we'll end with 140 - 145 volumes. We're entering volume 107 now with Egghead probably lasting another 30 or so chapters. Geographically, the Straw Has are still in the first half of the New World.
I think the course ahead could be something like:
Final Battle in Marijoa / the center of the world
Among them, Elbaf and the final battle could be lengthy stretches of story. Oda's going to take 9 - 10 volumes for the last battle alone. There are so many characters, I think it's impossible not to take that much time. Oda always seems to underestimate - or just not account for the 'action' segments of his story when making estimates. He birdcage was deployed on Dressrosa something like 35 - 40 chapters in; and then the arc lasted another 5 - 6 volumes. The tea party started in chapter 860, but Straw Hats didn't leave Tottland for another 40 chapters. Usually, it's a little more than half the story arc is focused on the big action set pieces Oda sets up in the first half of the arc (Alabasta, Skypiea, W7/Enies Lobby, Dressrosa, Wano).
Once Oda gathers all the pieces for the big final battle to liberate the world, it probably won't resolve particularly quickly. I think just the big fight will last longer than many are expecting the entire series to last at this point. Because I just can't envision Oda exercising restraint at that point. It's his victory lap. He got to the end of the story and now he can dump out the entire toybox of characters to great a huge spectacle. I just can't imagine, particularly after he spent 80 - 90 chapters on Onigashima, that Oda will go for something quick or understated when the story reaches that point.
Oda has cut away a few times on Egghead - but all of those scenes could have also fit in between Wano and Egghead - but were also directly related to things revealed on Egghead. Law / Blackbeard's battle for example was shown as soon as Oda revealed in the cover story arc that Pudding was kidnapped. Which seems to be the only real reason for Oda to cut away to that scene after the Straw Hats arrived on Egghead. That and Oda already did a big BB scene on Amazon Lily, so maybe he wanted to space them out. The Kid scene sets up Elbaf, but importantly, the context for why he's going there was dependent on Shaka revealing Saul being alive and well on Elbaf (so we can put together that he's the man marked by flames). And the Vivi / Morgans scene seems to be narratively related to Egghead as Morgans somehow has intel on what's happening - and the manner in which he's already twisting the story directly impacts the Straw Hats.