There's almost nothing externally different about the 5.2 and 5.9 so swapping to either one is esentially the same. Actually they're almost the same externally as the 3.9 ..... you just have 2 extra cyliniders. As long as you have the same tranny/torque converter that came with the 5.2/5.9 you'll be good. The 2 are balanced differently but if you keep them mated to their original tranny you're ok.
Really all you need for the swap is the V8's engine/tranny combo, engine wiring harness, and PCM. You should be able to reuse your exhaust and driveshaft if I'm not mistaken. You'll have to remove your radiator shroud because the V8 is longer, and the V8's use a different intake tube but if you're using an aftermarket CAI or round filter you'll be fine.
All your external accessories (water pump, a/c,alternator,pwr.steering) is the same between the 3.9-5.2-5.9.
You'll need the V8 motor mounts .... they're different from the 3.9 so make sure you get those with the motor.
I just did a swap putting a 99 5.9 R/T drivetrain into a 2000 Dakota that came with the 3.9. Was pretty easy really.