Will a bank take that into consideration?

@Chris Hernandez they should take the potential income of the rental into consideration when weighing to qualify you for multi or not.

All properties we do see that actually cash flow are in very rough areas or need considerable work. 

It's not a great rule of thumb that doesn't take into consideration a lot of other factors.

@Dillon Francis@Derrick DillHere are the general considerations regarding 401k loans.401k Participant LoansIf your 401k plan allows for 401k participant loans, the maximum loan amount is equal to 50% of the balance up to $50k.

A couple of items for your consideration (there are others, these are just my top pics):Limitation of Liability. 

House hacking might have some consideration for personal desires but even so most house hack (especially using a duplex) defer to their investment goals to kick started their journey.  

I will take into consideration everything that was mention. 

 :)That $1,500 a month translates to an $18,000 return on your $66k investment (27% cash on cash) before you take into consideration other overhead expenses you might incur... excessive repairs, renovations, rehabbing if the property isn't quite where you want it when you buy it, etc... but you get the gist of how rentals kicks wall street's butt!

This is the “121 Exclusion” and definitely worth looking into if there is any considerable equity in the property prior to the 3 year window elapsing.