Where did Herbert meet Hattie?

Where did Herbert meet Hattie?

Of all the copious records available for the Stetson and Haskell families, the one document that has not shown up yet is a.marriage record for Herbert E. Stetson and Harriet E. Smith—a significant omission considering the importance of that event to the story line. 

As we know, Herbert was born and raised in Sumner, Maine. Harriet Smith, called Hattie, was from a small town, North Bloomfield, Ohio, south of the Lake Erie port of Ashtabula. That corner of northeast Ohio was not far from Chautauqua County, New York, where Hattie's grandfather Captain Haskell had settled after leaving Plymouth. 

We also know that following their marriage in 1879, Herbert and Hattie settled in Earlville, Iowa, near Waterloo, where their five children were born and where Herbert served first as a school principal and later as an accountant and county auditor.

Sometime after 1901 the family moved to Deer Lodge, Montana, a mining town near to Butte, where Isetta and her siblings grew up. Herbert served there as a business manager for Bonner Mercantile, a dry goods store. 

Since we don't have the marriage record, the mystery is when and where did Herbert and Harriet marry, or how they even came to meet. Did Herbert come for a few years to Ohio where Hattie lived, perhaps to fill another teaching position before his later move to Iowa? Or did Harriet visit or possibly live for a time in Maine?

Since both their families had roots in the Plymouth, Massachusetts, area, could there have been some kind of family introduction that brought them together?

Besides the fact of their marriage, I've found no other record that places Herbert in Ohio or Harriet in Maine. So how they met and where they married remain open questions for now.