What you will find is they typically appraise for far less than the hands off cost to add the ADU.  

While I don’t typically work with real estate agents to find deals, I do collaborate with other professionals throughout the process.

When you leave, a duplex will typically generate more cash flow as a long term rental than a single family home.

The price point for a positive cash flowing single family house rental is typically 120-180k purchase price here so I am sure you'll be able to scale very quickly here with the capital you're working with.

.- Over a 10 year period cashflow will increase as rents increase (rents typically rise faster than property taxes, insurance, etc.)- The property should be appreciating, if purchased in a good location, increasing the owner's equity/wealth.- Rents will be paying the mortgage off, increasing the owner's equity/wealth.- If you hold a rental until death, you can pass it on with a stepped-up cost basis, limiting captial gains if then sold (limited by inheritance tax limitations).Too many newbies on this site trying to replace their day job income via "passive" real estate investing w/o digging deep enough to understand how it really works.

For example, a buyer putting 20% down on a $500k home would pay around $500k in interest over the 30-year life of a typical mortgage at a rate around 6.5%.

If this is the case then typically you only have to comply when you make alterations.2.

The repayment terms for a 401k participant loan are equal monthly/quarterly payments of principal and interest (typically prime plus 1%) over a 5 year term (longer if used to acquire your principal residence).Please note that if you take a full $50,000 and then pay back the loan, you can't take another $50,000 until 12 months after the first loan was fully paid back.Per the loan offset rules that went into effect with the 2018 Tax and Job Act: if you leave your job and the loan is current at the time you leave your job but then the loan goes into default because you left your job, you will have until your tax return deadline (including any timely filed extension) to make the loan current by depositing the outstanding balance into an IRA (and thereby avoid the taxes and penalties that would otherwise apply).Please keep in mind the multiple loan rules:Under those rules, the sum of the balances of a participant's outstanding 401k loans under a single 401k plan (using the highest outstanding balance of each loan over the last 12 months) can't exceed 50% or $50,000 whichever is less.

Just curious, what is a typical LTV I can draw up to with a HELOC on primary and investment property? 

Mortgages for LLCs with personal credit under 680 are tough and expensive, and under 640 are typically not really economically practical for the borrower.