SOunds like the woman is out in the sticks, and her pile of old iron isnt hurting anybody.
On the same token, she's sitting on it thinking that she's got a gold mine.
Sure, there are probably alot of good parts out there, but i'll bet the vast majority of it is total crap you'd have to pay somebody to take away.
At any rate.. it's her stuff, on her land, and it's not like she's got it sitting out on the road.. I say leave the poor woman alone.
As far as any enviromental impact her collection may have, anything that was gunna leak out of those trucks would have done so 30 years ago.