(They have the deferred maintenance you'd expect after a fixed income senior lived in them for several years, plus smokers, pets)So how do I turn 5 straggling houses into a proper real estate portfolio and well-managed rental business? 

I would make sure your property is properly marketed and that your rents are in line with the comps.

If it has gone up and down rapidly, then that indicates a boom/bust market (typical in areas without a diverse job market such as areas where all of the jobs are in tech, energy, manufacturing, a single employer or supporting those workers for example). 

Primarily when downsizing they question your occupancy intent (Claiming primary residence on a fixer upper for favorable LTV terms, with intent to convert to an investment in the short term) but everything can be worked out with proper documentation.

Take ownership of your mistake and learn to do the proper due diligence recommended above😊

I wrote a BP blog about how to screen tenants properly here. 

But then again, I've heard that as long as you keep everything up to par with the llc's basics  (separate bank acct, current llc status w state,  properly funded,  no co-mingling, etc) it holds up in court even if single member.     

I currently live in the metro ATL area, but have history and ties in Charlotte and Chapel Hill (Both NC).For work, we focus on logistics, senior care, and manufacturing.

I had initially sent her several listings in Madison proper, but apparently all 3 were already under contract. 

Nevada has many of the draws of CA and the added benefits of low property taxes that don't assess on sale, landlord friendly, no state income tax, and multiple tech and manufacturing jobs like Tesla, Apple, Google in the area.