Pulling the rear 3rd really is quite easy, I've had mine out in as little as 30 mins before... but I've done it several times, too.
Yep, you can leave the drums on. Ratcheting box-end wrenches are nice for getting to those 4 bolts on the back of the drums.

IMO there are 2 primary difficulties w/ this chore...
1 - unless your rear brake lines have been replaces before and have an unusual amount of slack in them, they will have to be disconnected so you can pull the axles out enough to clear the carrier... which means fluid everywhere.
*But there is a trick*
on the axle on the P-side, there is a T in the hard lines. If you disconnect the lines here, where they come from each axle into the T, you can quickly thread an M10 1.0 bolt in place where the line fitting was in the junction - this prevents all your fluid from leaking out. You'll have a little bit o' brake line still attached to the wheel hub, but it doesn't really matter when you slide it out.

2 - After you take out the 14 bazillion nuts holding the 3rd on, it will likely still be very stuck in place. There's a lot of hydrostatic pressure from the gear oil keeping it stuck to tke gasket and flange. It may take a few good whacks w/ a rubber BFG to break the seal. This can be a PITA while laying under there... and that sucker is deceptively heavy for it's size!! so be ready when it comes off.