I hiked the PCT/JMT from Cottonwood Pass to Bishop Pass Sept 15-22. We talked to the back-country ranger near Taboose Pass who said that the intensity of the smoke [starting in mid-July when the fire started] in any given location varies by day, but it generally stays low until about noon every day; then the afternoon winds pick up and moves the smoke up to higher altitudes.
We did not have any significant smoke south of Forester, even in the afternoon. But once we crossed into the Kings River watershed, we had smoke every afternoon. On 3 of the days it was quite annoying - not so bad as to be hard to breath, but definitely smelly, hazy/smokey and with reduced visibility of the mountains.
And to clarify Rick's comment, they do not plan containment in September - the forecast containment is not until Oct 31 (i.e. hoping for rain). As best I understand it, they are currently only trying to contain the western front and the northern front; I believe they are letting it freely burn south and east.
I think you're taking a pretty big risk w.r.t. smoke in the Tablelands area. If the wind does not cooperate, you're likely to have hazy views in the afternoons, potentially quite smokey. If I was planning the trip, I'd reconsider my destination to get out of that area. If you've got an alternate itinerary in mind, say from Mineral King, you might do that instead.
Of course, if the wind is coming from the south, you'd be AOK. It's a gamble.