I went thru this problem myself.
The first mistake I made is that I bought AWG 18 gauge wire. This caused lots of issues with crimp connectors.
I finally mounted my RAMPS1.4 to the frame using a wood board, and switched to AWG 22 gauge (22/4 shielded security wire). This wire is easy with crimp connectors.
It does not matter where you mount the electronics so long as the wires do not move relative to it (causes contact problems). You can then measure the wire from there to your motors and endstops. Mark your cables before connecting them to avoid confusion later. Taping them with clear tape also helps before using using zip ties.
Get yourself a good wire stripper like in the video posted by misan.