It's really helped me to narrow my focus at my day job and eventually will help with real estate I'm sure.Thank you for the book recommendations, I'll definitely have to check those out.

I've narrowed down to a handful of areas, and on paper Fort Wayne seems like it's full of potential opportunities.

You can probably get enough information to narrow down to one lender for a pre-approval letter.

Once you narrow it down to a few houses, then get your agent to arrange a showing.

However, I would just run numbers carefully on the properties you have available and start to narrow down areas in surrounding areas that have the most potential for growth in the city, appreciation, new infrastructure, etc. 

There are so many places to invest I am trying to use biggerpockets to help me narrow that down.

It narrows my focus. 

Once you narrow down a market or two then deep dive into towns and submarkets.

While I think the best way to learn these is through a mentor, is there any guide or advice on how to narrow down to learn the many subjects of real estate?

I think your problem is, the contractors are reluctant in giving cost when the scope of work is not narrowed enough.