It's quite expensive to start a fiber network. You might want to consider using wireless with a mesh network. In Detroit there's an organization that has become the leader:

https://www.alliedmedia.org/dctp

In Detroit it's not real high speed because they're using foundation money to provide basic access, but there's no reason I know of that it couldn't be.

Here's more information on the mesh network in Detroit:

https://motherboard.vice.com/en_us/article/kz3xyz/detroit-me...