I think it's not going to take that much longer, 4-5 years.
Outside of actual island based story arcs, Oda is pretty fast paced.
He just made GB capture Weevil just like that.
He just made Sengoku sail to x-location just like that.
He just had Garp invade Hachinosu just like that.
Those need no or barely any build up whatsoever and if Elbaf was the last traditional story arc, most of the following story can be taken care of in a similar way, cause not a lot of build up is needed anymore.
We know all of the characters by now, besides some HKs and the man marked by flames.
I think it's from now on comparatively easy for him to handle a sufficient pace.