Observations placeholder

My journeys start in common ways - usually leaving a duney shore with marram grass after walking out of a building.

You have probably symbolically left your castle [body and soul] have walked to the shore of your island - and you are then,  when flying out of body - flying beyond your body to get to other spiritual realms and levels

I launch myself into calm slow flight over a smooth sea with a flat cloud-base sky. I am always naked and have my golden ankh in my left hand. My skin always has a golden sheen.

 Golden sheen = strong spiritual energy.

You are travelling over the water level below the first 'boundary' in the air. 

The column soon appears and I enter it by holding the ankh against it. A kind of sliding door or sometimes an opening window lets me in.

The portal and tunnel

Once inside I am aware of space opening above and below. …..Once down I am in a forest, darkish with dappled light. Coloured birds flitting everywhere.  

Seeing birds is a good omen this forest is not a dark forbidding place it is a nice forest, but they are using it to show you this I think

I move forward through the upright trees. A dense rain starts to fall and I can see not far in front. A wind springs up stronger and stronger forcing me back but I redouble my efforts moving forward. An invisible hand seems to try to close my eyelids. I shout curses and keep my eyes open. Leaf-heavy branches thrash at me and prickly bracken catches at my legs. I move forward with increasing determination. Loud screeching sounds arise all around. I just never stop pushing on.

 Rain = purifying water, wind = breath of life

 All of a sudden things are calm and quiet. I am standing in front of a large fallen tree - horizontal against all the vertical ones.  

Grove symbolism creeping in.  A 'virtue' - an attribute in fact that needs to be set up again.  Virtues don't have to be ‘goody goody’ type virtues they can be anything - such as 'self confidence' or 'cheerfulness' or 'hopefulness'.

From under the tree extends a white sheet. I move close and see that it is covered in writing. The symbols are not familiar. I look around and my trinity are each visible in different directions. I sense them asking me to take out the sheet. I pull and it starts to tear. "No!" from the trinity. I walk to one end of the tree trunk and brace myself to lift it. It seems an impossible task. I strain with my arms around it and my legs bent fully. It doesn't move. I pour energy into this until I am aware of my muscles and blood vessels swelling. The pain is very sharp and deep.

I think you have symbolically restored a fallen virtue - so restored some attribute that had become dented - your trinity clearly wanted you to do it and the fact it caused you pain is a sort of indicator it was something that needed to be restored.  The sheet may be a clue to the type of virtue it was. 

A low groaning noise starts up and seems to mock me. With huge effort the trunk raises up and I stagger with one end of it to move it off the white sheet………………

I wake sweating and with aching muscles.

Not surprised!!!!!