I'd go for a stab wound rather than a slashing wound actually- almost all of the organs in the abdomen are tucked up into the rib cage behind the lungs, and even the kidneys are under the rib cage on the sides. A stab to anywhere between the last couple of ribs and the hips isn't likely to hit anything besides intestine, and the intestines are actually fairly loose in the abdomen, which is why sometimes they can get twisted around themselves and land people in the hospital. So one portion of the intestine may be punctured, but think of it like trying to stab jello- things move out of the way.
With a slashing wound, especially one that cauterizes as it cuts, unless it's *very* shallow, will do much more damage to the muscles, because putting those edges back together is that much more difficult. Because of the way the intestines sit in the abdomen, you're likely to do much more damage to them as well. Then, even if the edges have been cauterized, you still get the intestines and their contents exposed to the air, which will cause sepsis either from bacteria from the air or from intestinal contents into the abdominal cavity.
Edit: To actually answer your question, a wound like that- stab or slash- would probably mean several days in the hospital to make sure no infection has occurred then several weeks of taking it easy to let the muscles heal.
