Like everyone already said, a D60 & 14BFF are already pretty beefy, especially if your just running in mud. Some sort of traction aide up front would be great.. and like mentioned, if your budget is flexable enough, 35 spline stubs & hubs would be nice... but the 30's will probably be plenty.
Since mud = moisture, I would make sure you relocate your diff vent lines to as high a location as you can find, along with T case etc. Top of the firewall maybe...
Rear disc's will not trap and hold mud like the stock drums will. I'd still go with some diff cover guards even though you plan to run mud, you never know whats lurking in the stuff, like a log or rock. I'd also shave the stock lip off the 14 for sure to get the little extra clearance from it.. the extra drag in the mud could make a difference.
That's about all I can think of right now.