Q: The direction of existing (not changing) wood in kitchen/fam is from left/right. The other rooms are having new wood. Please notice I said rooms not area – - I like rooms with doors and with wood floors changing direction away the wood being places from the doorways rather than across the doorway.
So, I am thinking about (please speak freely) the wood floor from the front door, straight in, until it meets a line from “A” through “B” (a structural 5 x 5 column, probably square) to “C”. This will allow an opposing straight in direction for the kitchen, a diagonal across the dining rm so the Music/Liv is the long way, the hallway to be the long way from “C” all the way into the powder rm, and the office to be opposing straight in from that door.
I have read about window light vs floor direction – - am I in opposition to that? For a herringbone join, will some tongue and groove have to be recut? Is the 60 degree from A to B a problem? It is not 45 degrees. Also, is a third way to make this direction change slant cuts at direction change?

A: There is a bit of complexity to the installation method you suggest. From a DIY standpoint I would honestly suggest never trying to do work this complex unless you have relatively extensive experience with flooring or you have immense patience and time.
This type of work is possible, but I would suggest sectioning your floor off in very specific sections. Most of this follows your plan, but I would suggest using a 45 degree angle for simplicity. To get a truly flowing appearance, you will need to mate up each directional change. The other alternative would be to build a border around each directional change, but this will remove a flowing appearance similar to the difference between a direct change versus the herringbone change I discussed before.
Here is the sectioning I would suggest. You can keep a diagonal in the dinning room area and I would extend this area from the sliding doors all the way to the far wall where the entrance to your kitchen is. For your other border I would suggest drawing a line parallel with the wall where you marked point A going through the support post. For the hallway (C), the music/living room and the area between the walled in heater ducts and the support post, run this all in the same direction, parallel with the windows. Finally allow the office and the area along your stairs at the front door to run parallel with the stairs. The trouble here will be planning and executing the installation.

For transitions in direction you can carefully line up planks so that the rows flow as your directions change, but this will be difficult. Once the planning is done to line these planks up you can either simply cut the planks and install them, or you can carefully cut new tongue and groove sections using a router bit to marry up the directional changes on your planks. I would highly suggest keeping your diagonal area at a 45 degree angle as this will make the transition process easier.
The difficult area will be around the support post. Here you will have multiple directions all coming together. You will have the diagonal meeting two directions of flooring, so this leads to a few choices. The easiest way would be to extend the planks directly away from the diagonal in its appropriate direction (toward the front door or down the hallway/music room. This would leave you with a small area with a herringbone transition or you can allow this to be one area with a direct change.

For your office, I would suggest a direct change in a threshold area of the door as this will be the most simplistic change, but you could also do a herringbone transition. Keep in mind you will be doing this transition from both sides as the floor will continue on toward the powder room.
Keep in mind this project as a whole can be done to look very unique, but it will be a lot of work and a few headaches. Now, you can simplify it by not worrying to much about marrying the planks together so that each row does not seem to flow as the directions change. Also, with a few carefully laid borders you can section off each area of flooring, which would require much less work to get the various direction differences, but as I mentioned before this becomes very obvious and less of a flowing appearance. You can also use transitions to cover some of the gaps here, as this would work similar to a border between directional changes.
