The heaters initially lead into a small gorge where tricky boil lines can throw you for a loop. At extremely high waters (above 20,000cfs) the water can pulse 4 or 6 feet up and down the walls. Either side of the island on this section is passable. There is a small wave that can be surfed near the top of the river left side of the island. Once the gorge opens up the challenging part of the heaters begins. Because the river can be run at such a variance of levels it is difficult to say which line is the easiest. Typically if you stay right to center right things are safe but there are fun lines all over. You can get a real bird's eye view of everything from the scenic outlook on the Wilderness Camp road.