Okay, so...
So after thinkin about it, what Anchor's sayin', is that he'd like something automatic, totally unattended, and totally keeps mice away.
Gee, that WOULD be nice.
As noted, Mice look for nice safe cover, food, water, and bedding. They don't need a place to pooh- they do that everywhere. They don't need any particular source of bedding- they'll chew up everything in sight, and cram it into the most inaccessable, impossible place to GET, and, as a result, put it somewhere where you can't get it out.,
Case in point:
I have a 1971 Kaiser-Jeep Jeepster Commando... 43,000 original miles. Has the ex-Buick "Dauntless' 225 odd-fire V6, and a T-series (I think T-86... 3spd, first gear left and down). From underneath, the bellhousing is TOTALLY CLOSED... there's no access holes that aren't covered with heavy tin and bolts. The throwout bearing fork is totally shielded- not even a spot where you can stick a finishing nail through there.
A few years ago, I had problems with the starter bendix 'sticking'. Okay... well, I only drive it a couple'a times a year. I live with having to turn the key an extra time to get it to 'go'. A while later, I noticed the clutch was slipping. Yeah, well, it sat quite a while, probably sticky fingers in the pressure plate... so I keep workin' it to keep it free... doesn't help much.
Finally, the damned starter JUST WON"T GO. Solenoid clicks, but won't fling the motor. So I pull out the starter, and find that the solenoid and bendix are all wrapped-up tight with... yep... a MOUSE NEST. It's BAD... I can't even pick the crap out'a the bendix. Of course, it's an old reman, so no allegience to keeping it 'original, so I take it over to my favorite starter-guy... he tells me to reinstall the flywheel cover... Uh... it's never been off... and he swears that it's the only way I'd have a mouse-nest in there. Okay...
Go to install the new one, take a light, and look in the hole... and the WHOLE CLUTCH HOUSING is FULL.
So I go on a rampaging inspection, and find NO (and I mean absolutely none) point of entry.
WTH???
I'm still baffled... and I'm still pickin' pieces of cloth, newspaper, straw, string... out of the flywheel housing of my Jeep.
Fortunately, the Jeep was designed from the factory, to be able to FORD creeks. (even says how in the owner's manual!!! Ah, those were the days). Before I put it in the storage building (used to be sealed really tight, but I've since changed that), I pulled down the cowl vent cover, so it's not a mouseable entryway into the body... fortunately, the interior has not been compromised YET.
So here's how I dealt with the situation:
I took out one of the windowpanes in the barn basement window. I rearranged a few things in the barn basement, and slid open one of the hay chutes about 6"... and took one board out of the chute at the upper main floor. Then I put an FM radio by the big doors, turned it on to the local rock station. Raccoons don't like hard rock... but Simon (ex-USMC-type barn cat) goes through window, to chute, up chute, and into barn. He's got several spots of vantage, including up into the hay loft, where he keeps watch, kills mice and birds. When weather is bad, I know where he'll be- I've got a spot in there that's boxed-in with tarps, and an old bath-mat... and under that mat is a piece of styrofoam board... between 'em is a small thermostatic electric heating mat (about 4 watts)... so on a -20F day, he's got a cozy-warm spot to hang out and break the chill.
But Anchor's problem sorta precludes the use of somewhat-domesticated guardians.
You can't drive mice away... and you can't keep 'em from getting in. Their teeth grow FAST, and they NEED to chew with 'em to keep 'em worn down, lest they'll die... SO they pick something to chew on, that gets 'em into places we don't want 'em. Not a matter of IF, it's simply a matter of WHEN.
You can't trap 'em with a trap that doesn't automatically reset. IF you trap 'em, you'll have to deal with stinky dead mice.
If you poison them, you'll have to deal with stinky dead mice.
So your last two options are pretty clear:
Lure them away... give them reason to want to NOT be there... or
Leave, and surrender your property to their savagery.
Dunno how to do the former, but unless you're gonna give up, that's your only choice.
I'd say... get a Tin Cat trap, and rig it with a secondary stage... where a trapped mouse runs to one side of the tin, the tin flips, and drops the mice into a tin barrel with vertical sides about 4' tall... so that the mice CANNOT climb out. Set it up with really good *but inaccessable) bait. Yeah, you'll have a barrel full of stinky, dead mice when you get there... put on a clothespin, and carry 'em out to the bonfire... deal with the queasiness long enough to get the job done, and live happily knowing those 495 mice will not procreate and grant you another 32,031 more baby mice to dispose of.