SharePoint File Migrations - What the Hell am I Getting Myself In To

The File Migration is on in a big way in my company.  All file shares are to be migrated to SharePoint by 12/31/2019.

My company's organisation has Corporate sitting at the top as, essentially, a holding company.  Our divisions, work more like subsidiaries with their IT staff reporting to their local leadership, with no connection to Corporate.  Local does not report to Corporate.  I work for Corporate. 

The majority of our IT staff is purely break/fix.  The divisions are mostly in rural locations.  IT is an afterthought at best.  The IT staff comes down to someone who works at the division's child is "good" at computers.  What does that mean for me...  Well...  To put it bluntly, a lack of professionalism. 

Documentation is non-existent.  The ability to write documentation is... questionable.  Most of these people haven't written anything of significance since High School.  Yet, one of the requirements for the project is that they write a design document that will detail their SharePoint site designs with respect to their internal departments.  They also need to write up a security model.

I refuse to accept that the IT staff is incapable of doing this project.  Difficult, yes.  Outside their wheelhouse, yes.  The trouble I see is that they just won't want to do it.  The project will be labor intensive, and I think it will keep getting pushed to the side.

I'll need away to motivate the staff to complete the project, but how do you motivate a staff that doesn't report to you, doesn't like you, and doesn't particularly feel the need to listen?  On top of that, they are geographically disparate.  I can't throw an end of project pizza party.  I can't recommend bonus money.  I can't even send out McDonald's gift certificates.  One, because most of the towns don't have a McDonald's, and two, company policy prohibits it.

I feel like I'm between a rock and a hard place, and I really should be looking for the exit...  But I'm getting off on the challenge.  If I pull it off, it will be a crowning achievement for me.  Sure it won't look very fancy on a resume, but it will be a diplomatic and technical success...  If I can pull it off.