Your journey from the Navy to real estate investing is impressive.Networking with lenders and investors is a wise step, and you'll find lots of help and knowledge here to support your journey.

My financing knowledge is limited beyond conventional, private, and hard money.

Hire a PM co and stay out of their way :) Good luck 

Maybe working in the STR space just makes it hard to imagine that there is significant demand for longer stays?

We are fortunate to have found a place with great tenants who take great care of the place and want to stay there.

Success hinges on staying up-to-date on market shifts, funding choices, and chances for investment.

Stay curious.

I would probably keep the other house regardless of what I do because of the low interest rate.I am now wondering if I should hire a Qualified Intermediary (my realtor calls this an "Accomodater") so I have the option to buy a one level rental, stay where I am at, and if in the future I am unable to live in the two level home I am currently living in (our second home that is my primary residence), convert the rental to a primary residence.

I agree with @Wyatt Wolff that if you systemize it you could run it yourself but getting that in place with a 70 hour per week job could be tough and not worth the added stress if you're able to pay a PM to do it and still make a good profit.It seems like you have but definitely would check out Furnished Finder and Airbnb/VRBO for 30+ days stays to see the competition/average pricing,

To my knowledge I believe this is possible with a property purchased as an investment property, but would it apply to a primary residence turned investment property?