Whiplash:
Switchbacks? Oh, yeah, here they are on the map...funny, people seem to be cutting them in the snow...

Up to Parker Pass is patchy-ish snow - more snow than bare ground, though, I'd say, but the trail isn't too hard to follow. The pass is clear but there's a lot of snow on the other side. I think I ended up too low in the canyon below the pass and had to scramble back up to the trail below Koip Peak Pass. You can actually see the trail well in the talus going up to Koip Peak Pass - I think the wind is just blowing all the snow off that slope! Again, going down the other side, lots of cross-country in the snow. I ended up just aiming for Alger Lakes (frozen) and picking up the trail from the far end of the lower lake.
There's snow going up to Gem Pass, but when I was there it looked like someone had come through with a string of pack horses - !!! - and basically shoveled a path in the snow. Made it easy for me

On the other side of Gem Pass, much less snow, but stream crossings a much bigger issue around Gem and Waugh Lakes. Be prepared for high, fast water. The crossing right below the JMT junction had a good set of logs, but before that you're on your own.
Hope that helps! Here's Alger Lakes from just below Koip Peak Pass.