Well, I now have the computer upstairs connected up. I think the landlord previously had cat5 in the house-- there's a suspiciously convenient gutter cut into the underside of the banister rail, and handy gaps in the rims of the door frames... still, we now have ethernet cable going up the stairs held on by duct tape, as is proper :)

Drove in to work this morning, too cold and foggy to relish cycling. I've done just over 50 miles on the bike since getting the cycle computer. w00t.