Yer welcome. Always glad to help & besides, I get perverse satisfaction out of having a different opinion as everyone else.
One word on the ultra-sonic pest repellers. They don't work on some critters. They seem to work well on small rodents like mice & squirrels. On crickets ... not so much. On ants ... not at all. I'm thinkin that crickets make their own irritating sounds so they are immune to ultrasonics. Ants were just put on the earth to piss me off so it's no surprise that there's no way to repel them.
As far as where they are getting in your VX ... remember that a mouse can squeeze through a 1/2 in crack. Sorry but you may never find their entry point. For all you know, they may have pushed through one of the grommets in your firewall.