You do not mention the type of control system that you will be using. I am using DCS, however the wiring of the track may be independent of the control system selection.
My layout is 11'x22', with two yards off the around the room oval, going down a hallway type space. (my room is actually "T" shaped. I have four power channels going to 4 terminal blocks, equally spaced around the room, then wires from the four terminal blocks to the local track locations. I have an average of 9 sets of wires going from each terminal block to the track.
This design does a couple of things. It reduces the length of wire runs to the track, as I have 4 local hubs. This design would work with most (if not all) control systems. Also, I think it minimises the total length of track power wiring.
I run my switches, uncouplers and accessories off of different transformers, so as not to overtax the track power. In my case I have a separate circuit for each of the three areas above. I am using a Lionel 1033 track power to run the uncouplers, so I can select the voltage that best suits the uncoupling track. The switches use the fixed voltage off the same 1033. Accessories run off a separate transformer, and again, I have fixed and variable voltage choices. I have the saw mill running off the track connections, so I can set the voltage that works best for the saw mill operation. I have another 1033 that operates my Atlas turntable (again using the variable voltage to give the best turntable operating speed).
These were all wired at different times, as my layout kept growing. so there is no need to wire everything at the same time. Also, when testing and troubleshooting issues, it is easier to only have to deal with one set of wires at a time.
Be sure to develop a wire colour standard and stick to it. I also put a piece of white electrical tape with a label (in black marker) at the end of each wire, so I know what it is, and what it is connected to at each end. You would be surprised at how confused you can get over time. I now have over 3,500ft of telephone wire for signals, track detection and uncouplers, and hundreds of feet of each coloured wire used for track (black and red), accessories (green and yellow). I double up on telephone wire to activate my uncouplers. You could add other colours as well. Be sure to get the correct gauge of wire, and more than you think you will need. I have run out of wire many times, which can force you to modify your wiring colour standard (which I have done at great confusion to myself). There are others on this forum that could help you with wire colours and gauge.
Good luck. Planning your wiring, then doing it can be a fun part of the hobby. Run your wires in groups, general at 90 degrees to and along the table edge so the underside of the table doesn't look like a rats nest. I used a 4" piece of household electrical wire 14Ga, with the copper ground removed, then put a screw about 1" from one end, then bend the wire so there is room to "hold" the wires between the household wire and the underside of your table. You can easily slip more wires into this holder. I space my holders about 18" to 2ft apart, but whatever works for you is fine.
