3 days to swap chassis and the majority of the rear suspension here, working from 7:30 till 8 most days without stops (easy when you've got an understanding girlfriend like mine, Although she told me if I didn't turn up for a family do 4 days after I started I'd be in the sh$t )
My opinion is it's better to lift the body as one lump and wheel the chassis out from underneath. take a look in my thread in member's motors for body lifting ideas. to do this you need to disconnect, wiring, fuel lines and remove front panel.
after that it's the academic swap between chassis, worth replacing the A frame ball joint, and it helps to have a big club hammer for that!
I did use a fair bit of copper slip, and kept engine/gearbox and transfer all as one lump (so you need a big crane)
I didn't bother re feeding my wiring loom in the chassis, I used conduit from a discovery and cable tied it along the rail
Trick is to be thorough and work on one piece at a time, concentrate on moving an axle in one hit, don't start jobs and leave it. That way you don't lose bolts of struggle to remember how something went.
Be prepared for a 'mare with the fuel tank piping, new jubilee clips will be required