The Roads Only Pole of Inaccessibility would require a hike downslope from Ross Mtn peak to about 1400-1450m elevation. You could use the ridge that runs SE away from the peak of Ross Mountain to a bench at about 1695m elevation just NE of the spot and, depending on terrain, could hike the last 650 m (as the crow flies) to the curve in that stream channel 300 m downslope. The map sympbols indicate it is meadow so you can probably see where you're heading all the way. (LOL, I checked GEarth and it isn't meadow at all. The slope looks steep but I'm sure a dedicated hiker could manage.)
After spending a bit of time on GEarth looking at this location it appears that the Roads Only point is probably the Ross Gulch in the Johnson Corner area. Without ever having been there and using only GEarth and the photos people have posted in that locality to get an idea of terrain I think the easiest way to reach that point is to follow the ridge from Ross Mountain as described to the bench noted. You'll be above that bend in the Gulch on the east side where the slopes are less steep and you should be able to zig-zag across terrain to the point.
To access the Paved Driving Allowed Roads Only Pole of Inaccessibility you probably want to just take the Iron Mountain Trail up to the peak (2419 m) and hike downslope about 500 m in elevation (around 1 km best guess for hiking distance) along that NNW trending ridge to the north of that drainage above the Fish Fork campground down on the river.
Thanks. This was fun.
[1]: https://ironhiker.blogspot.com/2025/08/baden-powell-x3-and-r...