Take the front clip off - easy to do and will save time and your back from bending over the fenders. Also you won't need to try to figure out a way to get it out over the radiator if you have a lift.
Yes, taking the front clip off will make things easier. Barring that, even the core support off will make it a thousand times easier.
Just swapped engines in my truck, and had I pulled the core support in the first place, would have gone much faster, and I wouldn't have been as sore. Fenders removed would have made it exponentially easier.
Make your job as easy as possible. Concrete surface, good lighting, something to keep you dry if rain is a possibility.
Budget yourself a lot of time. The problems caused by rushing will be more difficult to fix, and may lead to problems when it's time to start the new engine up. If it runs now, when you put the new engine in, it should run then too. Watch for wires not disconnected or caught on things. Missed bolts. If you pull the knock sensor from the block you should get most of the coolant out of the block, which will invariably figure out a way to spill all over, even when you are sure everything has been drained.
I have a manual transmission, one thing I found much easier last time was to remove the engine mounts from the frame. Allowed me to slide the engine in pretty much straight forward and back, helping line everything up. An automatic won't have the same problems, but polyurethane engine mounts are sometimes also a pain to deal with the same way, and having those as well, pulling the engine mounts from the frame eliminated those as a problem too.
