Based on my own experience of writing a book on college scholarship strategies for low-income students, I think you could write a < 200-page book fairly quickly, perhaps in <2 hours a day for 40-60 days, especially since you already have a lot of writing material to pull from. (I wrote my 120-page book in a month by writing 1200 words every single weekday, about 1.5 hours of writing daily.) I used an accountability program led by a self-help author. One trick to quicken the process is to take a week to create a REALLY detailed table of contents so there’s complete clarity about what you (and your coauthors) need to write next.
I think there are a number of 80% solutions that are far better than this wonderful future book not happening at all. You could probably get an EA grant to either take a month off to write it or perhaps even a ghostwriter to compile 40% of the book from your blog posts based on your detailed table of contents.
If you’re open to self-publishing, you could give that 40-60 day messy first draft over to an intensive editing service at a cost of $4k-$5k. While I opted for self-publishing to update/edit it after it’s live and to set the book at a lower price, a publisher would probably make this way easier with marketing and in-house editing.
Happy to answer more questions. I’ll also potentially be making a tiny publishing LLC to publish my book that will have an EA-like name which you’re free to use to buy your ISBN if you want to also self-publish.
I’m curious why mass media campaigns would be the recommended action given that meta-analysis of mass media campaigns don’t seem indicate a reduction in sedentary behavior nor achievement of recommended physical activity levels, (though they do promote some increase in walking.) Lobbying to invest in the built environment seems cheaper and also more effective in the long run. Organizations like Strong Towns, Bloomberg City Labs, various walking and biking safety groups advocate/lobby for walkable neighborhood changes that are very affordable, if not free, like loosening zoning to allow for mixed-use buildings, multiple homes/businesses in one lot, reduced parking minimums. Many of the changes only require legislative change, since businesses or developers take on cost of new construction. Urban3 consultancy group has considerable research into the significantly higher tax revenues cities get from new residential and commercial developments, replacing underutilized spaces like parking lots. I would guess that influencing national health organizations (like national cancer or diabetes associations) to see walkable neighborhoods as possible could increase the pace of change. Other ways to get other groups to join the lobbying effort might be to clarify via mass media campaigns the link between car-centric infrastructure to the high rates of road fatalities (the main way to make roads safer is to build pedestrian/biking infrastructure (build buffers to remove “stroads”, bike lanes = narrow roads, sidewalk bump-outs = increase visibility, both of these decrease speeding). Or clarify the health impacts of children (developmental delays and asthma) for those who live on car-centric streets. I would guess these mass media campaigns would have a counterfactual difference (though indirectly to your goal) since road fatalitiy preventability and children health outcomes from even just proximity to cars are things people are not aware of, whereas almost everyone is aware that physical activity is good.