If you can get the front up on jackstands, you can drop the front of the subframe, loosen the back and let it hang. That tilts the engine forward enough to shift the A/C compressor out of the way and squirm the alternator past it out the bottom. I've heard of guys squirming it out from the top by either loosening the radiator supports or dropping the back of the subframe, but that's hearsay and not how we do it in the shop.