Historically, of course, dark-stained flooring was less a fashionable possibility and more a solution used to hide multiple imperfections in cheap oak floors. 

We have one breaking ground in Newark, OH in Licking County, a submarket of Columbus and it's ultra modern no garage testing the market for affordable housing. 

Learn all you can from resources like BP and other forums, then marry that with some old fashioned physical labor.

My window had a film over it for privacy- bt I nejoyed it more than modern day bathrooms with the fans

I plan on gutting the rest of the bathrooms and making them more modern than what's currently there. 

Hello BiggerPockets Community,I'm embarking on an exciting journey to acquire and renovate a duplex from 1900, aiming to tackle the inherent challenges of outdated insulation and the lack of modern vapor and air barriers.

@Kenneth Hynes LVP looks more modern and will help the apartment stand out.

Just get a proper home inspection and investigate the basement quality, electric type (i.e. knob and tube, aluminum, ungrounded, modern romex), plumbing type (i.e. cast iron, galvanized, pvc), and just be overall ok with an older building material.

About your concerns on rents: you'll be hard pressed to find an example in modern history where rents declined in a meaningful way, not even 2008. 

It's easy to pass them all by and find one with amazing ocean views and bad decor, or better yet a STR with modern decor and close to the ocean.