Sure enough, it was the wingless forward fuselage of a B-57 with the early A-model canopy. The tail has been neatly cut off just forward of the vertical stabilizer's leading edge, so no obvious serial number was available.
You can see an optically-flat insert in the canopy, over on the right.
This is the interior of the rear part of the fuselage. If that bulkhead marks the after part of the bomb bay - which by best-guess it seems to - then those blue things might be camera mounts.
While walking around the hulk, I found the bomb bay door lying face-up on the far side. The large placards indicate loadouts. The legible ones read, from top to bottom:
"Station 3
52 lb. flare (U)
80 lb. flare (U)
220 and 260 lb. frag (U)
750 lb. New Family
1000 lb. GP
M120 photoflash bomb" --I guess that makes it even more likely that this is an RB variant.
"Station 18
52 lb flare
80 lb flare
220 and 260 lb frag
M120 photoflash bomb"
"Station 9
52 lb. flare (U)
80 lb flare (U)
220 and 260 lb frag (U)
500 lb GP
500 lb frag
500 lb interim
M120 photoflash bomb"
The topmost one is Station 2; it's pretty illegible but it looks like the loadouts are the same as Station 9.
The next smallest placards say "Receptacle for Station [n] upper level store," and next to Station 18 there is a small, green placard that appears to read "79-SHIP-135."
Stations 17, 8, and 20. Sta. 17 and 20 are rated for the same as Sta. 18, while Sta. 8 is rated for both sizes of flare, the three sizes of fragmentation bomb, and the 500 lb. general purpose bomb.
The hatch (or panel) right aft of the perspex canopy was off, and though the fuselage was a bit taller than I was, I stuck my digicam in for a blind shot of the cockpit area. No seats, but you can see the rudder pedals, holes for the control cables, and obvious instrument panel sites. My guess is that the bit in the bottom left is part of the frame for the pilot's ejection seat, though it is somewhat odd that the frame is behind the perspex dome. Would the ejection process have blown off the panel I took this shot through, and then shot the pilot's seat diagonally back up and then out of the plane, or would it be more of a straight up-and-out?
Anyway, I couldn't poke around too much more than this because not only was my girl waiting for me back at the car, but the fuselage was sitting on what looked like high ground but was actually very, very wet. Anyone can find the fuselage in Google Maps by searching for 156 Clary Hill Road, Union, Maine. The B-57 is the long white object just to the left of the water hole right up the road, and behind the search-results word bubble that pops up. It's not a very distinct view, but it is there at full zoom.
