gDGBD (relative), fCFAC (actual) A.K.A. "Standard" or "Cripple Creek" tuning.
This video demonstrates how I play Ola Belle Reed's "Undone in Sorrow" out of standard tuning. First using a two-finger approach, then the typical overhand (or clawhammer) approach and, finally, a couple of different variations on the upstroke, up-picking or "Seeger" style.