If they want to sell it, then if they are truly a friend why not have them get an agent and sell it versus you trying to make a buck off your friend?

It included asset management versus PM   It included underwriting and value determination.

For the most part you can buy a home that needs a little TLC or a home that is run key.I would rather buy a duplex for $200K with solid rents versus a $800-$900K duplex in CA.

The total rents will be higher than SFR, and you are spreading the risk of vacancy (a house would be 100% vacant versus a duplex might be 50% vacant at a given time). 

Perhaps scrutinize more critically what is a capital expense versus maintenance.

Out in small town Iowa our Selfstorage development has dried up due to the high cost of building versus low rental rates.  

I would maybe even wager you are negative or break even just looking at cash flow.

Consider your upside versus your downside risks. 

There is a much bigger benefit to living in a SFH versus a duplex.

My recommendation is to focus on Stick-Built, Brick & Mortar property versus Mobile/Manufactured, main reasons; 1) Investor appetite, 2) Appreciation factor, 3) Re-sell value, 4) Future buyer/investor appetite.