However how did you continue to operate as an illegal duplex?

You would have to know what market rents are, what actual rents are, operating data, etc.

@Elisha CramIf you are operating this like a hotel or b & b, then you'll have to factor in self employment taxes as well.

Can you get the previous year's operating records so you can see what that costs?

The shower operates correctly.

And don't trust any pro forma statements they make, get the actual paperwork for rents received, operating expenses, etc.

You'll want to get all the real operating costs from the owner, including pest, lawn care, taxes, insurance (you can get your own quote), maintenance, utilities, management, etc. 

We had coin-operated washers and dryers on every floor of our residence hall.

My question is, Operating agreement is based out of the real estate strategy or standard for all types of strategies.

These vehicles aren't going to tie your assets to a single family property.In no way do I think TKs are a bad thing, I think they are great options for some people and a win-win for investors and TK operators.