If your going to regear to 4.56s, you should upgrade to a 31 spline traction unit and go with 31 spline alloy axles. Complete off-road or Randy's R&P both have great prices. COR also has the best prices I was able to find on the Yukon D44 chromolly axles and superjoints. You will also need a new crrier upfront with the 4.56s...might want to consider a selectable locker at least for the front axle...lots of stuff eventually get into up in AK, might as well do it right...you have already gone pretty far with everything else in your truck...upgrading the axles will mean that you can dependably put it through the paces without too much concern. If you will be running it much in the winter there, you may want to look at a selectable for the rear too (ARBs are strong and would work nicely). Several good options, but you are looking at about $3K in parts for gears, install kits, selectable lockers, axle shafts and U-joints) (give or take, plus install)...not cheap, but definitely a good investment....at least consider upgrading the rear to 31 spline chromollys when you regear the rear. Good luck with your choices.
John