We have a duplex in Norfolk that we house hacked. 

Do you see yourself holding this duplex for 10+ years, or are you considering other investment types moving forward?

I've been looking at duplexes and tri plexes but nothing has panned out yet.

The ability to turn single-family lots into duplexes or even split lots for separate units can significantly boost rental income and property value.

I was able to get a HELOC on the first one for 90K because it was a condo in Florida and doubled in value (has since crashed). 

A good friend of mine recently managed to pick up a modest duplex outside Phoenix that looked risky at first glance.. low rents, older neighborhood.. but with a few smart upgrades, it became a steady earner in under a year.You mentioned your worries about remote investing and the challenges of managing properties from afar.

Pete Beach has varying STR rules in different areas, and each condo HOA sets it's own stipulation on 3, 7, 14, 30+ day minimums.

I have a few lots in New Orleans and am looking to run  profitability analysis of sfr 3/2 development v. one zoned as duplex.  

You're right that it's getting tougher to find solid cash-flowing properties ($600 or more) in Grand Rapids, but the appreciation potential of a single-family home or duplex in Grand Rapids would be much better than that of a mobile home.

I own a duplex property (I do not live on site) and I'm renting out the 2 bed/1 bath back house.