I bet it's less than you could get somewhere else and you're building equity, learning REI, and taking positive action.

Only issue was that the town couldn't inspect footings and made them hire engineers to stamp on the structure and say it was safe.

In a case like this, if there is a mortgage, bet your firstborn the lender will bid to get the tax lien (potentially up to the market value or the mortgage amount) to secure first lien position.

I would also insulate the heck out of the space while you are down there (I'll assume this a crawlspace) just to be on the safe side.

So at what point do you feel safe buying the next one or two?

Your best bet is to try to find someone to work with/for in real estate to learn the ropes and make some money, put in a lot of hours and hustle, connect with as many investors as you can through local meet ups, and just keep grinding until you start seeing results. 

From what I've been learning, your best bet for a park of that size is to find an onsite manager. 

I would assume Fort Myers would be a good bet for you nearby. 

If on the schedule E I'd say you're pretty safe. 

If things continue after we discover  who does it, we think to liquidate our laundry room, we want to keep our place safe.