Never checked the seatpost diameter... will update eventually.
I picked up some aluminum randonneur bars, a sprung seat with rubber cover, and some nice gipiemme aluminum cranks at the local co-op yesterday (to use if I can't really service the BB and re-assemble the cottered crankset. I have new cotter pins and rubber hood covers coming from Niagara cycle, and some cheap 700x38 Nashbar Randonneur tires arrived in the mail Tuesday.
The idea is cheap randonneuring style gravel bike / baby trailer tower that I'll take out on the weekends. I suppose this is going to be a weight-no-object build. I'm leaning toward the Suntour Hero and friction bar-end shifters combination. I'll probably add fenders (steel?) after I see how much clearance the 38's leave me with - I think it's still going to be plentiful.