SSD, considering where you are and what you're likely doing there, I think it's much better to have time to plan and scheme than no time at all due to busy action day in and day out
But I'd say just skip the axle swap altogether, and instead simply run some good quality steel 2-1/2" hubcentric spacers between the inner and outer dual wheels. You'll get the outer tires closer to the bed side like you want, mud and snow will clean out much faster on their own, the only rocks you'll be able to pick and jam between the tires would be mini-boulder sized which are reasonably easy to see and avoid, and if down the road you decide you want bigger tires you won't have to worry about them rubbing sidewalls.