That depends

. I'm a real estate appraiser in Texas and I have a few rental properties.
First off, it may not be a good idea having your tenants living so close to you.
Would having a tenant knocking on your door at 10:00 pm complaining about a plugged up toilet and they have to go, RIGHT NOW, upset you?
It does happen, I can assure you.
What is the demand for rental housing in your area? Based on recent past experience, what has been the vacancy rate of this particular property? Has recent foreclosure activity in the area driven people to rental housing versus owning?
You indicate the cash flow from rental of two units out of three would cover the new mortgage payment. Will the new mortgage payment include PITI (principal, interest, taxes and insurance)? Make sure it does.
How are you arriving at a price to pay for the property? Have you looked at recent sales prices of comparable rental properties? How many similar properties are listed right now/how many have sold in the past 6-12 months?
If you decide to run with it, do you have the resolve to put away a cash reserve for replacement of short-life items/repairs to the property, and a cushion for when a tenant moves out and you have to wait a while between tenants.
When I was in my 30's-40's I'd take a chance on just about anything, but now I'm a heck of a lot more conservative about investments.
Many questions to answer before you take the plunge.
If you have more questions about this possible investment opportunity, I can try to answer here, or send me an email off-forum if you'd prefer.