They can identify potential investment opportunities... not to mention all the tenant/landlord laws, eviction process, security deposits, accounting, end of year tax statements etc. lots of pitfalls to be avoided.wish you success in your ventures!

Talk with some securities attorneys, brokers, lenders. 

Safeguard reached out to me when I was in my mid 60s, and offered lending notes secured by real estate. 

Not that it really matters.No institutional lender will give someone a loan that doesn't have:1) Credit history2) A social security number3) Income3) Employment historyYou'll want to research Wholesaling and Land Contracts.

We were not able to recover any yard damages due to other damages they had left that needed repair, which empted out their security deposit.

I do a lot of private lending and we do make some passive interest, but the good fixing flippers make the bulk of the money.

Which one is more appealing - continuing to own the house or the security of that much cash/liquidity?

Depending on your debt to income, you might have to sell or have an executed lease to secure financing to buy the second home.

Is there a private entrance/parking or room to make one?

So, your focus may need to pivot from high rental cash flow to little to no cash flow as a rental with an appreciation upside.I would recommend taking your $150K to $200K and securing a solid equity position in something that will cover its expenses and maybe provide a small cash flow, but then is poised to appreciate nicely over the course of the next several years.