My wife and I spent four days hiking the loop from the West Fork Foss River over the high route between Chetwoot and Tank Lakes and back through Necklace Valley. The reports on this hike, both here and at nwhikers.net, are very helpful, and I won't repeat a lot of what is said there.
We stayed the first night at Big Heart Lake. The route from Big Heart to Chetwoot is well-defined and easy to follow as it goes up the ridge between Big Heart and Angeline, loses elevation as it angles toward Angeline, then climbs again to skirt the cliffs above Angeline before dropping to a saddle and then climbing to a pass above Chetwoot. Not difficult, but not fast either. Taking our time we got to Chetwoot for lunch.
From Chetwoot we headed east up a large talus slope (skirting it when possible) and then traversed a steeper talus slope under the cliffs of the NW ridge of Iron Cap. We camped that night on a level buttress that juts out under the cliffs on the north end of that ridge. It was a spectacular spot, with grassy campsites amid slabs and boulders, though water availability might be a challenge sometimes. The only tarn with water remaining in it looked pretty unappetizing, but I found good snowmelt by climbing down from the north tip of the buttress.
The next morning we rounded the ridge, still traveling on talus, and followed the draw up to Iron Cap Lake. From the lake we climbed NE on an accommodating series of slabs, but instead of going up to around 5800', as a number of others have done, we followed a bench (identified by Beckey) at around 5500' that contours around the north spur of Iron Cap. The route, which is cairned pretty regularly, drops steeply to about 5400' to get around the cliffs on the northern tip of the spur and then quickly regains the elevation once the tip is passed. This was Lisa's least favorite part of the route because it's steep--not really exposed, because there is a band of trees below you, but the grass and heather on that steep a slope can make for slippery footing. The bench continues along the east side of the spur, with some ups and downs, skirting the cliffs above, until you reach Iron Cap Pass. Most of the bench is covered by talus, so it entails a lot of boulder hopping, but apart from that it offers a pretty straightforward route. From the saddle we climbed up to Tank Lakes, where we spent the night along with a sizable chunk of the local mosquito population.
We were glad we broke the off-trail part of the hike into two days because it allowed us to take our time. The boulder-hopping is extensive, and since a lot of the talus slopes are quite steep, it was good to feel like we had plenty of time and could take the necessary amount of care in negotiating them.