Shouldn't be that insane. Front axle is a cake walk, the rear will require a swap.
The front GM kingpin Dana 60 is identical spindle to spindle for DRW and SRW applications. You would just need to find a set of DRW hubs and rotors and slap them on (the rotors are idential, except for the diameter of the stud holes). They can be found used for a reasonable price, because all the offroad guys who snatch up the Dually K30 trucks for the front axles swap the DRW hubs out for the narrow SRW hubs. You may be able to trade out the SRW hubs you have for DRW ones and net some cash on your part to the right person. Any one of the 4X4 forums should net you many people who would be more than happy to trade you hubs (and pay you). Keep it in mind that your SRW front hubs are gold, they sell new for at least $250 each, and used ones can fetch nearly that becasue most of the new ones are aftermarket. I'd say a used set of SRW hubs is worth $275-425 depending on condition of the rotors and DRW hubs are worth less than $100 a pair unless the rotors are mint.
In the back again you would have to swap out the entire axle. If you swapped only the hubs to the DRW style you would narrow your SRW axle from 67.5" to 63.5" and would have inner tires hitting your leaf packs and inner fender wells. This is the combo that was on the cab and chassis trucks, but the springs were only 36" apart, which is about 8" narrower than what you have. This won't work.
Your locked 4.56 rear axle is gold to a 4X4 guy, and you may be able to sell it or trade to get a dually 14 bolt that is the correct 72" width. Alot of the dually pickups came with 4.56 gears, so you may even luck out on that. You can find a Dually 14 bolt out of a pickup pretty easily, or a Dana 70 if you wish. Personally I like the 14 bolts more, becasue they are much easier to set up gears, are cheaper and there are a ton out there.
If you find the right guy to trade parts with, or purchse used parts at a good price and sell what you have you could end up with a zero dollar swap, or maybe even net some money.