If you really want to get rid of the smell you will need to pull up the pad and carpet......paint the floor with any old exterior paint you have around or kilz  oil base and put down new pad and carpet.  

Does it make sense to lock away the $20K and cashflow better, or finance the whole thing and keep the extra pad?

With the 70% rule of thumb, I have: 120K * .70= 84K ( minus repairs which I, off the top of my head and with, hopefully, much padding have at $40k) = $44,000 for maximum price. 

I would like to get some feedback on using the Wholesaling strategy as a Launching Pad for my REI career.  

The house needs a total rehab,  and the recent update makes me want to put the brakes on this project.

Only shared housing I would do would be limited to top end collage areas and Airline crew crash pads

In addition, you need to pad vacancy and utility, which would further eat into your profit.

I have seen RV parks that are nothing more than pads.

You got used to the sounds of the air brakes and it was far enough to one side of the yard, the front yard was huge and really wide, and the view from the house partially obscured blocked by landscaping.

So, buy removing the wheels and putting the mobile in a permanent place, usually on a concrete pad, and putting skirting around it, and filing the correct paperwork with the county, some banks will lend against it.