While rear disk seems like a great idea, you will find that if you simply swapped the disk axle over to the once drum brake rig, your braking ability may go DOWN.
The disk brake caliper pistons need much more volume that the drum brake cylinders.
The only reason I would swap those axles is for added payload capacity, and if the DRW axle has a better diff than the D60. Most come with limited slip.
The DRW axle looks to be either a Sterling 10.5 or a Dana 70. Only way to know for certain is to see a shot of the pumpkin.
With all that said, the full float D60 isnt a bad axle, provided you do not overload it.