In my houses, I make sure kitchens and baths have all romex circuits (grounded) and then try & add one grounded circuit per room to supplement the ungrounded knob & tube.  

. 🙄 what suggestions do you have for me to get my feet off the ground and past the financing a part?

It also had an above ground pool.

Then tear it open and dump it on the ground about 10 feet in front of the hole..wait for them to come out (about 8 or 9 am most will be outside anyway (or back at their owners home).If its cold, raining, night or afternoon expect them under the house.

@Richard UpdegroveIt blows my mind, but we've seen on the ground what you're saying about short-term rentals/Airbnb in Colorado.

They were crawling everywhere on ceiling, walls, ground. 

Or @Engelo Rumora I know those are a couple of guys with there ears to the ground.

I should have PM'd you guys links to the Meetup group--we'll sometime the last week of this month (April) but haven't decided on the exact dates yet.Rikako W. it's a little bit of a complicated story but, essentially, the house was marketed and priced as a 2 family, although there were 3 separate units, all rented out and all above ground (there is no basement at all).

Test a location about 2 feet up into the return air duct at both the return grate and the furnace end.

Also, be sure the oil tank is not below ground, or that there aren't any abandoned tanks below ground.