We happened to already have an RV hookup with power/water/sewer, plus a small bathroom building nearby that's about 10x10 split in half, one side with a toilet/sink/shower and the other with a washing machine. 

If I wanted to be more involved I may have considered starting a real estate biz like wholesaling, flipping, property management, etc.So, I would first determine how much time you want to 'invest' along side that $200k. 

I have a background in design and hospitality so I pair that with my knowledge on the real estate side of things.

But then on the positive side you've got the amortization of that loan, the tax benefit of depreciation and whatever appreciation there is.

Watching the forum's ebb and flow and hearing both sides can help you.

Depending on how much liquid cash you have, you could also invest too on the side if you are looking to scale rather quickly. 

So it's definitely possible, but I have seen the other side of the coin too often. 

I'd be in one heck of a situation if I had all of my units go vacant for a month or two, and expect to have that money to pay expenses...and no safety net.However, what if you could take your side of the equity and find your feet. 

When using the rent estimator for a duplex, is the rent estimate it returns for each side or the total for both sides?

It would involve putting an external staircase on the side of the house and making the second bathroom into a full bath.