Great hike, somewhat challenging on the way up. Bring a bear bell! There's tons of elk & black bear tracks although I didn't actually see any large game. Gets a little cold (October) in the campsites by the river, so dress warm! Very wooded so the views are limited, but if you're looking for a beautiful walk thru the woods, this trail is awesome.
This is an absolutely gorgeous hike.
Take the COUNTER-CLOCKWISE trail if you plan on doing the full loop. If you don't, you'll have one ugly uphill hike at the end of the trail. I/we know this for a fact. While trail guides list this as moderate with "gradual slopes", it's much more than that when you're dog tired and face that mountain going uphill gaining altitude.
Water in the river was plentiful. Even thought we trusted the source, filtering is still the best option.
There are a handful of riverside campsites. They are all first-come-first served. Even so, while we were there we encountered only one other hiker during our four day trek.
We did this as a three day/two night hike but could easily have been condensed to an overnight. Lots of great campsites along river and several others on the shedroof divide portion. Not many water sources on the shedroof divide trail so be prepared, but the Washington side had tons of water. We added the trek up to little snowy top fire lookout to spend the night and it is totally worth it, amazing views of Idaho, Washington and Canada. Did not see any bears but plenty of bear signs, make sure and go prepared. With the addition of the lookout and some minor backtracking my GPS said our total loop was 17.7 miles. And BTW there is way more elevation than 570 feet, probably closer to 4000 feet once you factor in all the ups and downs of each valley you cross. Overall great hike, highly recommended.
Doing this in one day is an incredible slog whereas two days is a beautiful hike. If you start up high on #535, you walk a closed road for a mile an then get beautiful scenery for many miles. A good camping spot is on the shoulder of BIg Snowy and there is a little spring in wet seasons a little ways down towards the basin. Or you can go on down into the basin and find lots of spots and water. This year, they are doing a lot of work on the trail in the basin, so call ahead of time to Sullivan Lake RS. Horses are not allowed until they are finished and it may be closed occasionally to hikers.
My most favorite hike anywhere even though my first time I hiked the last 3 miles in the dark ill prepared with no light source. It is incredibly beautiful and if you are looking for an escape from the crowds or mountain bikers this is the place. I rarely pass anyone on the trails even with 50+ miles of hiking in 2 days. The loop can be done in one day (not 48 hours as the guide says) but you must keep moving as it does take an entire day of daylight. Starts out up high and then many hours are spent in the forest along the river, there are about 3 different water crossings with the last being one I haven't been able to make without getting wet. After the last major water crossing you will begin to head up and out (approx 3 miles -- my nike+ ipod always runs out of a charge during this section!