sounds like your Fox has learned your routines and such, have you considered one of those large havahart traps? thought i saw one on craigslist recently. i've read several times over the years that fox will move their kits if they feel threatened, keep walkin around out there, maybe she will move, probably not. sometimes you can see the game trails near the creek, look for poop and tracks right on the deer trails. also, the kits are real active right now so if you keep an eye out you may see them and get a better idea where they live
good luck, keep us posted