Either you or a representative you trust with out exception must perform all the necessary due diligence just as you would for a property down the street from you.Turnkey companies want to maximize profit by doing as little work as possible using the cheapest materials.I would have a professional inspector check everything with a fine tooth comb,especially the roof,plumbing,electrical,and HVAC systems.Also make sure you get a repair warranty for when things go to hell in two years or less(and they will).I honestly don't trust any property I don't rebuild myself with my trusted contractor and quality materials that will last at least a decade or more

<-- income capped, meaning middle class and modest income only, but HUGE for those below the threshold.Mortgage interest deduction.Property tax deduction.Being able to write-off maintenance/repairs on your rental properties.For Californians, Prop 13 is a huge boon to buy-and-hold REI.There's a reason that entire books, intended for the middle class and others that aren't paying $10k/yr for CPA services, have literally been written about how to maximize tax goodies associated with owning real estate. 

Any suggestions on how to maximize my experience(networking, getting info, etc.)? 

This is what you can do , leverage that 500k windfall that you now have , look at getting 3 duplexes in the 550k range, put 25% down on each , a mortgage of approx. 400k won't be unmanageable , hopefully after debt servicing and operating expenses, your net should be about 1k on each , and if you can manage these yourself maybe you can maximize your return.

This will maximize the equity you'll have when the property is fully renovated and leased.

I totally get your point about best interest of the investor and maximizing ROI. 

I'm ultimately trying to maximize my cash-on-cash return, so I'd like to put as little down as possible.  

Need help: 1) figuring out how to best leverage existing properties and 2) maximize the $100K cash.

I'd take the following steps before quitting the job to maximize the possibility of getting traditional funding:1.

This is a strategy that people use when a couple plans to acquire a lot of properties to maximize the number of conventional loans they are eligible for.