The 4:10 gear swap for the original axle is the simplest, depending on your abilities may be the best option too.
https://www.stovebolt.com/techtips/axles/1%20Ton%20Upgrade/

Debatable, but the best upgrade is probably the 14 bolt axle swap from a Cab and Chassis truck, which you may already have (not from truck with a pickup bed).
It's all good except the work involved with spring perches and brake backing plate location, all that detailed here. In the end you get brakes with available parts, and your choice of ratios down to some even faster than practical.
https://www.stovebolt.com/ubbthread.../14-bolt-axle-swap-info.html#Post1249600

The 18" wheels look real nice, kind of define these 1 ton Dually's, but the practical upgrade is 19.5" wheels with 8R19.5 tires.

•1951 GMC 250 in the Project Journals
•1948 Chevrolet 6400 - Detroit Diesel 4-53T - Roadranger 10 speed overdrive - 4 wheel disc brakes
•1952 Chevrolet 3800 pickup
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"First, get a clear notion of what you desire to accomplish, and then in all probability you will succeed in doing it..." -Henry Maudslay-