I ran it in early august two summers ago and the gauge was just below 2 ft. The top two days before the airstrip were super boney, but some of the best scenery. We ripped the floors out of several rafts, but that was in large part due to poor packing and putting things on the actual floors of the rafts. At 2 ft I didn't think that there were any rapids that qualified as class IV. It was a really relaxed trip in terms of WW. The scenery and hotsprings and hanging out on the river for a week are well worth the trip. We even saw several river otters, which was a high point for me. Not a trip to be missed if you have the time or the money. One low point was that there were lots of bees at several of the more popular campsites. Bring benedril and possibly an Epi-pen (you're a very long ways from help). Also, loon creek is probably not worth the hike with your boat at that water level, but the hotsprings are great. If you putin at the ranger station, take your kayaks up and run Dagger falls, it's easily the hardest rapid you'll see on the trip.
Joe