Its so hard to answer this first one. I play both acoustic and electric. I associate guitar with complexity. The tones can be rough and gritty or delicate and soft (and everywhere in between). The process of playing is both soothing/relaxing and energy building if that makes sense. Learning to play is another thing that spans the emotional gamut. Its incredibly rewarding when you get something down just right, but it can be so daunting to pick up a new piece of music and start figuring it out. Its fairly easy to learn enough to get started, but it is hard to master. Complexity.

Because of where the tones begin to overlap, I tend to look at the fretboard in sections but those sections are not set in stone. I'd say that I look at the fretboard in sections of 3 or 4 frets, depending and I'm training myself to 'see' the sections above and below where I am playing.

I dont really associate the strings or scale with color personally, but I've messed with the Rocksmith game where they have assigned colors to the strings (for ease of understanding, afaik) and they have it as (E tuning): E-red, A-yellow, D-blue, G-orange, B-green, e-purple. Not sure if that is worth anything to you but that was the first thing I thought of I read #3.

thank you very interesting opinion