What are potential challenges one might face being an out of state investor and from self managing one door in state to hiring a PM to manage multi?

Finding someone who understands the 70% rule, the 1% rule, the BRRRR strategy, etc seems to be the challenging part for me so far.

You can always find deals, coming up with down payments can be a challenge. 

So here it goes:1) Single with no wife or children: House hack with an FHA loan, lower down payment which lets you be able to use the other cash left to leverage for another property. 2) Single but engaged or Married with no children: House hack again with an FHA loan, but move out once the 1 year stay requirement is over, and rent the other unit out.

@Emeric Harney based on your situation things are a bit more challenging. 

By the way, this is a  state law that most people will not know and will challenge but this is why you must learn MN law on your own. 

They all rent @ 2%+ what I paid for them and we've got them all in great shape.Now looking to offer for sale as a package deal and move on to the next challenge.

S8 can be very challenging due to their lower social standards.

As said before, owing a VHR property that can be arctic at times presents different challenges, but can be rewarding. 

The challenge if it goes to court is proving it really took you six hours.