Two things you can do that will really piss her off without doing any damage or harm: Dump tyres, preferably still on rims in her front yard late at night. It will cost her $5 per tyre to dump them anywhere. Or if you can get hold of a supply of stuffed white goods like dryers and bar fridges they are even better because they can't be disposed of easily. Don't dump either too frequently but do keep gdoing it for a reasonable period of time. Other option is sticky or greasy crap in her letter box.