draw out the workflow and improve orthogonality

[njtierney]

There is a bit of link-back to facility_user_dist.

I wonder if I can write down a workflow of several functions working together to do the analysis and then get results...as opposed to running monster functions that return smaller monsters with smaller bits - make it all smaller, and the functions more specific.

[njtierney]

Have a look at the tidy tools manifesto for inspiration about this.

Also make sure to re-read these sections on writing R functions:

• http://adv-r.had.co.nz/Functions.html
• http://r4ds.had.co.nz/program-intro.html (all of the "programming" section)

Actually, read all of these first, then come back to thinking about how to refactor the analysis