Level plug should be in the housing, on the right side, about the level of the footboard or slightly above... to the rear.
The brake boot... strip the linkage off the rod, then use a sharp cold chisel to free the metal backer of the boot from the axle housing. When installing the new one I usually remove the spring, slide it all the way up the rod until it seats, then use a piece of pipe or some such drift over the rod to get the backer seated into the housing. Then you reinstall the spring.
You can either drain some oil off before you start this job or run that side up on a couple of blocks to chase the oil to the other side...