https://drive.google.com/open?id=1ADrlKfg7BaYPRSy1OuNp-PgQe2q-chr3
A group of South Bay riders are doing this route this weekend as part of a three-day two-night ride. I'll be amazed if they're able to accomplish it in its entirety this early in the season. I have to imagine the Croft section near hwy 88 is dirt jeep trail, which after the rains will be mud city.
Looks fun, the adventure starts where the pavement ends, after all. Actually I'm pretty sure the only part that is unpaved is that section that kind of parallels Mormon Emigrant Trl through Pilliken. I've ridden N. South Rd and Silver Fork Rd, both are paved.
But yes, you are right, some of that could still be impassible due to snow up there, I'm not sure.