A good place to start figuring out profit/cash flow is to search the forums for the 4 Square Analysis. 

Also, if you buy using a hard money lender or cash, Zach Starnes can do re-fi's off the appraised value shorter than the typical 6mos and then you might not need any money down if you buy at the right price.

Still good cash flow. 

It has a lot going for it from a long-term rental/cash on cash return perspective, but I’m not too sure about short term rental demand and occupancy.

I've seen many people suggest a cash out refi but I like the flexibility of the heloc.

So seems like a decent play for cash flow but not much for appreciation.

If you aren't familiar with Baltimore, I would suggest it's a hard no and say that you are trying too hard to make cash flow happen talking Baltimore and tax liens and auctions.

I would restate that the lease will remain in place until such time that a new tenant is selected and moves into the property.This approach will ensure your cash flow while acknowledging that 'stuff happens.' 

Then over the course of the first year or so, if you could raise the rents by a total of $1k/mo (they are currently $2k, $1k, and $1k), then you might be able to pull out about $60k-$80k in a cash out refi. 

Eventually people die off and the homes go up for sale cheap, get abandoned and the park owner picks em up cheap and takes in the extra little bit of cash for the POH rental.