I frequent Calaveras and is open all the way through during the weekends.
The Alameda / Fremont side is relatively clean considering the construction activity going on during the week. if anything, some very light dusting making the roadway appear to be dirty. Additionally, I have noticed there are a couple of turns on the N bound, down hill side that have some un-even pavement (dipping). Just treat every blind turn as if there is the possibility of dirt on the roadway and you'll be okay. Have fun! :ride