Just completed this section in the Natl Park. Good water at Russell Field, about 30 yards downhill of the "official" source, a reasonably sized pool, clear and cold. There's a note in the shelter register ziploc describing where to find it. Apparently the rangers are telling people there's no water there but that's not correct. Derrick Knob shelter, we didn't get water there but met others who had. Silers Bald shelter, a smaller pool of water, not as good as at Russell but still possible. Double Spring shelter, we met three southbounders who told us it was totally dry. No direct knowledge of Mollies Ridge, Spence Field, or Mt Collins shelters.

Hope this info helps someone! Happy hiking!