They were abandoned and needed significant work which wasn't a huge issue but in terms of HUD owned properties i heard there can be significant processing periods.

If a tenant buyer does not exercise the option within the three year period of time, then we can do a couple of things.1. let's say they leave early.

It is still a seller's market in many geographic locations, so you can ask potential buyers for an extended closing period and/or with options to extend the closing period. 

Keep in mind of the I/O(payments/period) and game plan on how fast you'd like to pay it down. 

Quote from @Fred Scott: Sunrise Capital Investors - Mobile Home Park Investment FundI've seen a few posts about them here but none of them actually talks about what the actual annual returns have been.They are advertising heavily for passive tax deductions which is fine but what are the actual returns over a period of (say) five or ten years?

If Tenant is late in the payment of any installment of Rent or Additional Rent, orin violation of any other covenants or agreements set forth in the Lease (a “Default”) and the Defaultremains uncorrected for a period of _____ days, then Landlord may, at Landlord’s option, undertake any

Its one of the few where the low periods are nowhere near as slow as others.

There are quite a number of things that can make utilizing an FHA loan more difficult such as more barriers during appraisal, appearance of low qualification/little cash, typically longer closing period, likely higher interest rate, and PMI cannot be dropped without a refinance if 3.5% down.That said, just chain 5% down conventional loans, and make sure your duplexes pay for themselves.  

@Eric Smith A 1031 exchange with a related party is possible but comes with strict IRS scrutiny and holding period requirements.

That pain could take the form of working long hours, putting other aspects of your life aside for business, or uprooting your entire life for a short period to escape the rat race.