I would like to sue and also report the owner (licensed broker) to the state (Wisconsin).

imho the 121 and 1031 are two of the best features of the tax law benefitting real estate owners. 

I'm guessing the owner won't provide financing for you?

@Wai-Lin William Maw You may want to talk to some experienced park managers and owners in the area who have done the same thing.

He categorizes transactions, reconciles accounts, manages payroll, collections, builds & sends owner statements to clients, and generates our p&l at the end of the month.

Look at lists of properties that are on the Sheriff Sale, and Tax Sales, as some of those could have assumable mortgages, and provide a list of potential assumable mortgages, where the owners are potentially losing their properties.David KrulacBigger Pockets Podcast guest #82  

I'm unsure what the right path is, but I've been reading & watching podcasts about investing in owner-occupied, single family properties.

For example, an owner headed to foreclosure might sell you a property "Subject-To" where you take over their loan at a LOW LOW rate which changes the math a LOT when analyzing a deal!

I learned a lot about which properties do well & the importance of the owner's values. 

I went to all of the owners and was clear and honest with them about their current returns, expenses, ROI and potential future returns, every single one of them transitioned out of that investment class.