As stated above- multiple knives with good steel that are sharp. Only thing I've found that dulls a knife faster than pig is cardboard. We hang them by a noose around the neck and skin and gut with the guts going into a old cattle lick tub. Once gutted and skinned, we use a reciprocating saw and start at the pelvis and split the spine going up to the neck. You'll need someone to hold the legs apart while doing this. This part is easier than it sounds by a long shot. Once it's split up the middle, if the hog is more than 200 lbs, we use the saw to cut each side into two pieces a little bit in front of the hams and throw them into the cooler, and then cut the spine behind the skull and throw the front shoulders/ ribs into the cooler. We usually smoke these pieces whole without deboning. If the hog is 150 or less, it's usually just the two sides- left and right- that get tossed onto the smoker. After smoking, we remove the bones and start chopping.
Sharp knives, tarp for shop floor, gut bucket THAT IS BIG ENOUGH, and a recirprocating saw.