Yes, there's still a good-sized operation in Cloverdale, and the track is still in fair shape to get there. It's a long way from the next freight stop to the south, but there's no serious reason not to go there. SMART will probably, some day, get to Cloverdale with a couple of trains a day, anyway, if they don't totally trip over their own feet in the next few years.

The trip from there to Ukiah will be much much more difficult and expensive. In addition to river and other mundane issues, there's a collapsed tunnel to fix, and a few bridges that probably have more rust than steel in them by now. While Cloverdale wouldn't be massively expensive, Cloverdale to Ukiah realistically would be in the hundreds of million$. For, perhaps, a short train or 2 a week from the remaining small mills if they could be convinced to ship by rail? Ukiah to Willits would be a similar sum, for no reasonably likely traffic. Should be easy enough to do the back of the envelope math, though you'd probably need a high-priced consultant to make it all stick.