How close is it to public or school  bus stops? 

Especially to someone you want to borrow money from.QuickBooks is an expense account.

Is there a way to borrow money against the properties(not interest only or equity loans, but an actual convention loan) to purchase more properties?

Never had one get stopped up and have never had a problem with them.

Only accept cash or a Cashier’s Check for credit checks and if you choose them as a tenant, make sure only cash or Cashiers Checks are acceptable, Otherwise they can stop payment on checks and money orders once they move in.

When the properties stop appreciating at their recent high rate, I expect rents to continue to appreciate to narrow the gap between the property appreciation and the rent appreciation. 

I had more than on contractor borrower of mine that finally figured that out got enough equity from relatives and now they are doing quite well and no way we can compete with them.but you start moving up north of 750k to purchase and unless your in the Bay area or prime LA  that does knock out a lot of competitionand you also have to remember this poster is paying CASH  HUGE difference as she has no cost of capital most of us need to borrow and if your borrowing HM which 95% have to as banks really don't service this niche ... her carrying cost ona say 700k project would eat up 20 to 30k EASY.. 

It stopped about a month after we closed escrow.

So, I borrowed $15k from my roommate for earnest money to secure the property, advanced another $15k or so from my credit cards to cover points and closing costs, and advanced another $20k buffer (using 0% interest promotions on the cards -- I also had perfect credit), and bought it and celebrated.I had a contractor lined up that was a referral by my realtor, who had sold me my own home.

He wanted the 0% financing he saw on the window, and only then learned that he didn't qualify, having never borrowed money, and so he grumpily wrote a $12,000 check for the cheapest new car he could find..... despite us begging him to buy something a bit larger and safer.