I drove my tacoma up to the historical site without any problems in the morning (~1 mile from the trailhead). A car with chains on the fronts was also nearby. Took me 20 minutes to hike to the trailhead on the crunchy snow. Someone in a larger vehicle had driven out past the trailhead. In the afternoon their tracks were really wet and slushy. Below the historical site the road had its soft, muddy spots for a couple miles but I made it down without any oh-crap moments.
Photos (click for slideshow):