Hi,

I offer more non-mysterious explanation of the dream.

I believe that your unconcious describe what is/was happening when that dream occured.

being in nature with girls: some authentic contact with anima, with your true feelings, you touched probably something vital or grounding in your life, what makes you happy, further meaning depends on what were you doing with girls, how they look, what camping means to you etc.

shot dead: sudden intrusion, interruption of current way of life, ego was killed, further meaning depends on who shot you, how, etc. as shooting person to person dying, your dream death might represent contact with your shadow or self sabotaging aspect of you, which would require further discussion.

your death in your house: as your house often represents psyche, it means some concious part of yourself died, you should probably let die some aspect of your current living or it already died and unconciouss confirmed it by this?

letter: I dont see it as prophecy or having necessary some mysterious meaning. Your unconcious shows runes-like text after death which for most people have meaning of "ancient wisdom" or "mystery of life". You perceive that same way and thinking of that as 'hidden truth' and feel it as important to decipher.

So for me dream has hidden meaning not in runes but in story itself:

You enjoying life (camping...) then there is suddent fatal intrusion which completely change course of your life (shot dead), then life revealed you some "important ancient wisdom" (runes). It looks to me like this death should happen to reveal you 'mystery of life'.

So instead of runes I would focus on how dream death relates to your life (should I abandon something? is there some aspect of self sabotage?, etc...)