I face the same issue with my L-shaped layout. The wiring is color coded and was installed to various terminal blocks according to the voltages. Helpful, but not a "gold standard."
My layout has five separate platforms, and each one rests on sawhorses by the force of gravity. The wiring is held in place with cable ties, so the wiring grid is relatively neat. But if a home relocation was imminent, I'd re-do the wiring from scratch and do a much neater job.
With 20/20 hindsight, I should have:
* applied a wire number to each wire (both ends) for identification or trouble-shooting. With numbered wires, I could have created a WIRE LOG for reference.
* installed terminal strips at each side of the seam between the platforms, with numbers for ID; then create short "jumpers" for connections. When the time comes for disassembly, the jumper wires could be disconnected at the terminal strips, then re-installed when re-assembled according to the numbers. A time-consuming procedure upfront (when one is usually eager to get trains running ASAP), but VERY helpful when the layout must be taken down, transported, and set up again.
Perhaps this confession is out of bounds, but at age 80 I'm not likely to ever relocate from this house. After my passing and boarding the Celestial Express for a one-way trip, the layout will go to the following owner of the house. My widow won't want it, so she'll let the new owner deal with it.
Mike Mottler LCCA 12394