I just did a 14 bolt sf conversion yesterday, and it's not bad. My brother had a few dead framed plow trucks that were heading to the boneyard, so we pulled the good stuff. As far as plug and play, you'll need quite a bit of adjustment to the stock e-brake to allow for the larger drums, so make sure you can get the adjustment bolt free. If using drum, the stock cables will work fine. Can't tell you much about the disc brake conversion. The yoke may be interchangable, but I didn't even check. Precision makes a U-joint (Part #447) to convert from half ton to 3/4 ton. That takes care of driveshaft. I believe NAPA carries them. Seeing it now, I would have rather gone with a u-bolt flip. It looks much neater and less chance of catching things like rocks and small children offroad. Shocks bolt on fine. If you have a rear sway bar, you'll have to either lose it or weld the mounting perches onto the 14 bolt. I just pulled mine.
Both trucks that we pulled the 14 bolt rears from were early 90's 2500's. Unless it's a heavy duty 2500, they will most likely be 6 lug 14's. Sounds like your hardest part is going to be disc conversion (if you do it) and re-gearing. Just take your time.