You could always take Bear Valley road off Hwy 20 across from Hwy 16. It starts out as a dirt road, but a good dirt road. I've been on it several times.
I've been on it before as well, and you're right, that is another option. It's a toss up, either way. I prefer to stay off I5, so I guess I have options.
https://www.google.com/maps/dir/39....513cdf38bc879!2m2!1d-122.5445485!2d39.3750411