I wrote out a long reply a couple of days ago but apparently I never posted it lol. Oh well.
This is actually one of the reasons I'm planning to revisit this event for the 100th anniversary. Since a lot of the path isn't particularly well-documented, it's hard to discern how the intensity changed from location to location (other than to say that, as
@Western_KS_Wx mentioned, it was basically violent from start to finish). Even in places for which there are a lot of photos, most don't focus on the very worst of the destruction. I'm hoping I'll be able to find enough new stuff from some of the smaller towns and rural areas to start filling in the gaps a bit.
Anyway, West Frankfort and Murphysboro are definitely the first places that come to mind. Obviously the huge death tolls really stand out, with multiple instances where homes/buildings were swept away and everyone inside was killed, but the contextual damage in those places was also pretty extreme. Some of the aerial shots from Murphysboro are incredible:
This one in particular reminds me a lot of Udall:
And obviously the aerial film gives you a good sense of the scale and severity of destruction even with the sketchy quality:
https://digital.tcl.sc.edu/digital/collection/MVTN/id/3249/rec/3
Having said all that, my suspicion is that the actual peak intensity may have occurred in Hamilton County roughly around the time it reached its max width of a little under 1.5 miles. Somewhere between, say, Olga and Lick Creek. A bunch of rural homes were totally obliterated in this ~13 mile stretch with multiple fatalities recorded at seven different locations. A number of victims were carried considerable distances, including two that were thrown over half a mile. There was apparently significant scouring and high-end tree damage in many areas, and while I haven't been able to confirm it, multiple accounts mention parts of the Lick Creek Church's concrete foundation being "pulled up" and/or "blown away." On a farm west of the church, hogs and sheep were hurled in all directions and some were said to have been skinned such that they "looked like they'd been turned inside-out."
Both of these pictures are from slightly west of where I'm talking about, but close enough. One man was killed here near the Franklin/Hamilton County line:
Another was killed here near Olga: