Ask Gerold Biner, Air Zermatt, what he thinks, or Heli Austria, or any of the Canadian mountain/Heliski operators that fly day in day out in the same mountains and weather. When I hear discussions on IFR, EGPWS, PC 1, applied to mountain flying I automatically discount the source. Really, the 139 with its 40,000' business jet avionics and automation trying to mix it with the real mountain flyers?? Maybe with a mountain and location experienced pilot as Crab points out. Mountain flying is all about not getting trapped, even if you spend an hour hovering in front of a rock or a tree until the weather changes again. Allowing yourself to go IMC and then think you can bore your way out IFR is not an option.