But the low cash flow of those units gets a big assist in the overall return due to the outstanding historical appreciation (~$100K of market appreciation - not counting the value add) in 5 years since purchase. 

You can request copies of all permits for the project, outstanding code violations, zoning information, outstanding liens, etc. 

That will show all outstanding liens against the property.

My real estate agent is relatively new, but he's outstanding.

Fix the outstanding permit issues, (fix leaking gas pipe, prove basement original/make it uninhabitable) update panel, FIGHT CITY TO KEEP BASEMENT.

Some older parks fudge on the number of units parked.Have septic inspected and water inspected and tested to ensure you don't have any hidden problems that could cause you 100's of thousands to correct.In Maryland verbal or handshake agreements can be legally binding, have a real estate attny review any Sale DocumentsVerify 3-5 years  of income and expenses.If you are buying the park as a business entity have an accountant verify the books, Ensure Seller gives you copies of State and Federal Filed TaxesCheck for current Insurance and Have insurance company list any claims in last 3 yearsCheck with courts to ensure there are no outstanding civil lawsuits filed against Seller ,company or ParkVerify Verify Verify

If the loan is not repaid according to the specific terms than any outstanding loan balance can be considered a distribution.

The vertical income of flipping is fleeting however buy and holds are a more longterm play.

Ask for any outstanding maintenance issues upfront. 

Outstanding post!