However, with my units that rent for $1300, the $300 hit wouldn't be a major concern.

It's the best source of information that I have found concerning real estate, bar none.

I'm concerned I could not get a loan on the property as-is though & I don't want to tie up cash to sit on it.

I am actually at a place where cash flow is only my #3 concern with investing. #1 being appreciation, and #2 being debt pay down.  

And often it is the tenant who is slippery or hesitant about an inspection or slow to alert you of an issue that causes the most concern.

If you are concerned more about liability than a tax shelter, consider a large umbrella policy on your homeowner's insurance. 

My biggest concern is if they circumvent me and go straight to the owner as everyone might think but the trick is the owner doesn't want to deal with realtors ;).

One of my concerns would be managing the park since I don't live right there.  

There are other FHA requirements concerning which you should contact your local lender, but determining whether or not a triplex or fourplex meets the self-sufficiency rule is a good place to start as this rule will immediately eliminate many properties from your search, especially in expensive markets like ours.

I think having someone to give input concerning ARV and the thought process.