I just spoke with my gf to prioritized destinations and (I hope) worked out a more viable schedule.
I'm sorry for dragging this post out for so long, I appreciate all your patience.
12/12 noon leave Denver, arrive at night in Arches NP (camp)
(12/13 - 12/16, Arches + Zion)
12/17 noon leave Zion > arrive at night in Bonneville Salt Flats (stay overnight)
12/18 noon leave Bonneville Salt Flats > arrive at night in Napa (stay overnight)
12/19 noon leave Napa > arrive in SF by dinner
12/21 afternoon leave SF > arrive at night in Redwood NP (stay overnight)
12/22 noon leave Redwood > Seattle
[12/23 + 12/24 (am) is buffer]
btw, I noticed that Cootrip.org lists both Vail Pass and Loveland Pass as having "Icy Spots", what alternatives do we have that are more direct than driving along I-80 (so we don't lose a day)?