Just a quick followup. Here's our revised plan...
Hike in to 13 Falls and talk to the caretaker there. If they recommend not trying for a place just outside the 1/4 mile around Galehead, we'll instead hike up the Franconia Brook Trail. When we get to the ridgeline, we'll head toward Garfield. There's supposed to be a water source a short way down that trail. If we find it and there's water, we'll fill up and reverse course, hiking toward Galehead. FarOut thinks there are several places to tent along the ridgeline within the first mile or so of that stream. The topo map certainly looks promising in that stretch, so we'll probably find something. The next day we'll continue over to Guyot. If the water source turns out to be dry, we'll keep going south to the Garfield Ridge shelter and tent there. This seems like a fairly robust plan, so we'll likely stick with it unless somebody either on this forum or at 13 Falls gives us more hope of finding a place closer to Galehead. FYI, the Wilderness officially starts 66 feet south of the ridgeline trail per the last post in the thread "official boundary description of Pemigewasset Wilderness", so the 200foot requirement doesn't apply here. Tenting is legal within the first 66 feet of the trail on the south side and whatever you want on the north side. That said, we'll likely try for 200 feet if we can and if not, then at least not visible from the trail.
--junebug