Project Planning

I am currently designing in my head and on paper an image for this county wide commission I have been selected to be a part of.
It is coming along at a slow pace but it is coming together. I have been listening to a lot of music that fits my ideas and am processing different ideas from the lyric content of that music. My creative process is random. I have these lightning storms of ideas and I tell myself I will remember them but rarely am I able to. Along with keeping this blog updated more often I am going to start a journal of these ideas so I can reference back in the future when creativity runs dry. Sounds like a good idea and I know a lot of my influences kept them and it was discussed a lot in photo school.
So back to the project. I am to come up with one or two images that explains who I am as an artist and how the local landscape has helped shape me. The word landscape can be literal or interpretive. I have a solid foundation of what I am going to do. That was pretty tricky for me to settle on as I had several ideas. Now the fun part begins, the location scouting. This has started with google map searches and will soon transition over to driving to the possible spots and watching the light. I planned on starting that in the morning, but storms are lined up on the forecast.
So I ask you, how do you go about planning a large scale project? What are your methods?