I'm sure it's super easy... bench seat comes out with four bolts, new ones go in with 8. The four center bolts (2 per seat) are already in the body of the truck plugging the threaded holes. It's a pretty simple bolt out, bolt in process.
Not sure on the center console (buy one out of a hardbody extended cab) but I think it just bolts in too.
I haven't done this yet, but I spent the better part of a day tracking down phantom seats found on
http://www.car-part.com at junkyards that can't seem to keep their inventory updated.
FYI the seats you want are out of the Pathfinder up to 95, even though the D21 truck made it to '97. Found out the hard way that 2001 QX4 seats don't fit. Shame too... they were black leather and mint
Good luck!
Heath