And then again, there is always the trespassing option. If a property owner was unwilling to allow inspection, you can bet that there are undisclosed problems. Aerial photography will never equal the resolution you can get by walking under all those trees. And no amount of photography will reveal buried problems or other ecological contamination that might be far more expensive to correct than the property is worth.
Google earth isn't very high resolution, and the images can be rather old. That, however, might be a HUGE advantage anyway, as the Google Earth Pro includes a history of the aerial photography. By comparing changes in the property, you might discover all kinds of changes. A picture of a big open trench filled with trash taken 5 years ago might tell you a lot about the property. 20 years ago, there might have been a farm sewage lagoon present, or an auto salvage yard. I have looked at properties from more than 30 years back, on the occasion that the aerial photograph history goes back that far. In general, the older pictures always have very low resolution.
I'd be more inclined to look for public records on the property. County & city records on a property often include a history of building permits and code violations. I suspect that there are also state & national records concerning ecological violations, but I have no experience with finding that.
My first step would be to check with county or local property tax records, discover the ownership of the property, and then look into the owner to see what financial problems can be discovered. Some sales and most auctions are forced by financial necessity. Discovering the nature of that necessity might very well tell you what you need to know.
I bought a property many years back from the "land bank" of our county. Naturally, it had no warning precautions on the listing nor published drawbacks. A little bit of digging for information and talking to folks familiar with the location revealed that it had about 200 tons of sandblaster sand that was widely believed to be contaminated with lead-based paint. The California bank that held the note never paid the taxes to keep it out of the land bank property sale, so the concerns were real enough to keep them from retaining ownership of the property. It was zoned for industrial use and had an 8000sq ft building with an overhead trolley crane in it, so something had to be wrong to just let it all go.
There was never any provable history of lead contamination, so I bought the deeply discounted property and dealt with the sand pile on my own.
