I’ve been puzzeling over what Helen experiences in the mountains? …and after much thinking of possible senarios, it’s the simplest that actually fits:

The weather closes in, and Helen, pausing for a moment loses her way, stumbling about she finds a cave at the foot of a ravine. She shelters, keeping herself warm and awake till morning, saving her water and eating the dried fish sparingly. The following day the weather is not improved – perhaps worse – and she stays put. But by now she’s tired. She knows she must stay awake to stay warm and tells herself stories, makes plans, anything to keep awake.

Bit by bit, Helen gets cold and it becomes harder still, to stay awake. She gets delirious and falls asleep entering a dreamstate, finding herself in Valholl.

There are also the homes of the gods … Valholl, the dwelling of those men who fall among the dead in battle are slain by weapons, and who liver there with Óðinn. They are called the Einheriar (lone-fighters) when they come to Valholl. It is a huge hall, for it has to house many people. One sign of its size is that there are five hundred and forty doors, and eight hundred warriors at a time can go through each one. When they are not sitting drinking, the warriors’ daily activity, once they have dressed is to put on their armour and go out into the courtyard where they fight and kill each other. When there has been enough fighting, they jump up again, fully restored, and trudge back inside to the drinking.

For their food the warriors have the meat and flesh of a fat ooar called Saehrimnir (Sooty-sea-animal), which is cooked every day, and is sufficent for all the warriors to eat, however many there are. In the evening he jumps up again and the flesh returns to his bones for cooking the next day.

Whilst in Valholl, Helen gets to hear of a great threat to the world. There are, she hears, a group of men intent on changing the natural order of things, of breaching the (the shaking-road and is both beautifully coloured and strong, and a greater work of craftmanship than any others that are known. It is normally invisible to humans. It is only when rain and sun occur together that it is revealed in all its glory, and ignorant people call it a rainbow. It is composed of burning fire, running water, growing grass and the golden colour of the sun. the dead ride this bridge on their way to their future dwellings, and it is a beautiful sight when they spur their white horses up over the many coloured bridges) and harnessing the immense power it holds to generate electricity to sell for profit.

She wakes from her delerium to find the long-shanked aged man, Gangleri tending her and keeping her alive. Her natural intelligence supposes that everything must be a dream, until Gangleri begins to talk about what she has seen. He leads her out of the mountains, but not until she promises to help Gangleri to stop the scientists from destroying the world…

The details of this of course might change, but I think this outlines a much clearer and reasonable plot.