If your starting point is on the south side of Kelso, GMaps will route you on 432. But if the starting point is around the center of town, it is shorter to cross the river and take 411 south. 411 is also labeled 3rd street, and streetview shows a wide 2 lane, with light residential and business.
432 on the other hand is divided, more of a truck bypass road - reflected in the name Terminal Way. After their intersection, 432 continues on 3rd, with the truck traffic from Terminal Way. Closer to 433 it is labeled Industrial Way.
A further detail, GM, if using Terminal Way, suggests staying on that to Oregon Way, and then south. Not much difference in distance, but it looks like Oregon way is wider and lighter traffic.
Basically we are dealing with alternatives in an older port town. The time and distance differences are not large.
The first time I drove through this area, in the 80s in a rental car, I took WA4 along the north side of the river, viewed a covered bridge or two, and camped at the WA state park at the mouth of the Columbia (just behind sand dunes). The next day I crossed the high Astoria bridge, and headed south along the coast. After camping a night in the coast mountains, I turned east to Salem and eventually Bend.
On another I have crossed the Longview bridge (from US30), and just followed the signs to I5 (and then WA503 to the south St Helens area).