Your kit looks good.  Would it make sense to add a cellphone charger, and/or a an old cellphone that doesn't have current service but might still be good for a 911 call?
What's in your office kit? What would you add as sub-zero temps and snow looms on the horizon? 
My employer is moving soon, and it may be possible for me to keep a small office kit in the new location.  We'll see.  For now, if I take the train, all I've got with me is in my laptop bag.