Hello Sam,
"Welcome"
As for weasels, I have always found them around wet areas like a roadside ditch. But again I have found them in areas where pine marten are too.
If you're in snow look for their tracks while setting for bobcats. I would hang a beaver carcass in a tree for cats and set a weasel box trap down at the bottom of the tree off to one side to catch those weasels and civet cats. Use beaver meat, muskrat for bait and if you're a duck or grouse hunter throw some chest feather in the box traps for eye appeal.
Good Luck
JC