That contrary to Oda's communiction about the series' end, there are still ~6-8 arcs left, both large and small. When you piece together things Oda has said and what it directly stated in the manga, it becomes apparent that we must visit certain locations.
- Egghead: given, we are here and Vegapunk is being tackled along with Bonnie, Kuma and maybe Kizaru. 40-50 chapters.
- Beehive: Has been strongly hinted at a visit due to 2 things: Blackbeard taking Koby, and the fact that the Marine base near Egghead has Helmeppo, who is gung ho about rescuing Koby. Theres also the fact that Luffy and Koby have not properly interacted during the TS. I doubt BB is defeated here, but i feel like this island is largely necessary. Even hints from Jean Ango stating he knows where ALL of the Level 6 inmates are hiding do seem to suggest they are in one place. Beehive does seem like that place under BB. Maybe the SHF incident is also here. 40-50 chapters.
- Elbaf: This is obvious, and is even more necessitated by Vegapunk's quick FB, Usopp's dream, potentially Urouge if it ties into Sky island/moon lore, etc. 60-80 chapters.
- Lodestar: As much as people say this place is pointless, it wouldnt have been mentioned multiple times if it at least isnt meant to be touched on. 20-30 chapters.
- Laugh Tale: Obvious. 60-80 chapters.
- New Marineford/Mariejois: if this if the final war location, then yes, these are happening, especially because Sharley's prophecy and Noah involve some cataclysmic event eventually. Mariejois is right above FI. 100+ chapters for its content.
- God Valley: this one is largely a guess, but imo the series ends here. Any character who might be the final antagonist (Im, Rocks, BB, Shanks) has potentially some connection to the island. The WG erased its existance for a reason, which is peculiar. I have this funny feeling that its the most important location in the series. 60-80 chapters.
I understand thats anywhere from 300-400 chapters left, but its this feeling i have mixed with Oda's tendency to spend longer on content than he intends.