It is simple math.   

The ROI on the cash flow alone would be 30%-80%+/year if you could actually get a property at over 1.5%...Here is some basic math on how the ROI works:Ex/Deal #1) -$100k PP, $20k down/invested-Loan payment and all monthly payments excluding utilities =$500-$600/month-Gross Rent =$1250-$1750/month (@1.25-1.75%)-Net Cash Flow =$650-$1250/month =$7.8k-$15k/year on $20k Investment =40%-75% Yearly ROI in just Cash Flow

If my math is correct, you will only receive $71/month/door for cash flow. 

A secondary question, I want to start an LLC with the first property, how do I keep the business finances separate if I using a home equity loan?

Buy a SFH in a secondary ring of the market, rent it by the room or just do a simple long-term rental.

It is simple math that the market with the higher rent appreciation rate will always eventually produce better cash flow than the market with a lower rent appreciation rate.The eviction and missed payment rate in San Diego is one of the lowest in the nation. 

Everyone of our San Diego properties has appreciated at least $1k/month over the hold period (the best has appreciated over $4K a month for 21 years - do the math if you want). 

There is a lot of math to pay attention to, but especially pay attention to the DSCR number.

Usually don't sell by cap rates for small multis but lets use it to give you an idea of what I mean: Saving $5000 a year at a 10 Cap (lazy math) should add 50,000 to the value.

I’m keeping an eye on the math to decide if I want to keep it as a rental property, or sell it in the next year or so and invest elsewhere...