Paying Off Mortgage Quickly for More Cashflow

[Patrick Dunn]

I will preface my question by saying that I am brand new to real estate investing and I lack just about all knowledge on the subject so forgive me if this is a stupid question.  I have it in my mind that I would like to buy a relatively inexpensive duplex and live in one side while I rent out the other side.  Obviously the tenant on the other side would be covering the mortgage payment and more on top of that for rent so I would be living basically rent free.  My plan would be to put all of the tenants rent payments toward the mortgage plus payments of my own to pay off the mortgage as quickly as possible so I am making straight cash flow on the property.  After the mortgage is paid off I would buy another duplex and repeat the process.  My question is, is this doable and am I simplifying this?  Is there any downside to this approach?  Thanks in advance for any advice!