Plumber goes out and says its stuffed with wipes, tampons, plastic bottles, condoms, toys.... you get the idea.

I've never dealt with Septic in a park, but plenty of experience on SFHs.My advise would be 1) Find out the age of the tanks 2) Find out the material they are made of (concrete or plastic) 3) Same for leach fields.Reasons being: Old concrete tanks are far more vulnerable and likely to fail soon....the newer plastic tanks will most likely cause you no problems for a long time.So if I personally were to find out that these tanks were all plastic, and <10 yrs old, I would barely even worry about this.

There was also a thick plastic covering the ground.

We put on tyvek suits and opened the windows that worked , broke the glass on those that didnt , threw fans in the windows for 4 days before we went back in .( neighbors complained about the smell and the closest house was 50 ft away )  We made a pump system and used a new plastic trash can and sprayed with a garden hose over 100 gallons of a bleach , soap and water over floors , ceilings and walls just to sanitize as best we could . 

Dump trailer, Air Compressor,, 18 gauge Brad nailer, framing nailer and 25 gauge pin nailer, sledge hammer, contractor grade trash bags, gloves, eye protection, ear protection, plastic, painters tape, frig tape, list continues, about 100 more but my fingers are getting tired. 

PLASTIC PIPE: Some builders in the Sacramento area used PEX water pipes in constructing homes.

Evidently, he buys retail water and trucks his waste out the door in a plastic bucket.     

I'm not sure if finding the cheapest CPA to help you with tax strategy or the lowest-cost plastic surgeon is the best place to try to save money - you might be missing out on tax savings opportunities that out way the cost OR in the long run it will come back to haunt you.

One on top of each other and the outer layer is thick plastic sheeting stapled,- There's exposed wall from the back room to the garage,- Low hanging ceiling fans that are head height and drooping,- Small side room has no wall to the hallway.

AC included fully insulated garage and sheet rocked along with man door and way more flat work than any other production builder and of course real Hardi plank  NO plastic siding :).. etc etc. so you pick off your buyer that wants quality or price within reason.