On you question of just removing the engine and leaving the transmission in: I would recommend pulling engine and tranny as a unit. Main reason is lining up the clutch and transmission input shaft is MUCH easier with them out of the vehicle than attempting to do that when putting just the engine in. It can be done separately, but trust me, you'd need probably 2 more guys helping to accomplish it.
The recommendation of using a leveler on your hoist makes way more sense if you're leaving the front clip in place, because you'll need to tilt the engine/tranny as they come out to clear things. The same thing going back in place.
Gather up your buddies (or new ones you track down here on Stovebolt) to help out. Make a party out of the job.