Is this a potentially good deal for a buy and hold?

[Aubrey Kincaid]

I just found a house for $270K here in Billings, MT. It has a one bedroom one bath back house and the main house is a 4/2.75. Normally a four bedroom can rent for between $1,200 and $1,500 and the one bedroom for between $300 and $600. How do I figure out if something like this is a good deal? Is there a formula for this. 

I am a total beginner and this would not be a place that I would occupy personally because I'm already in a great place with my family of six.