mothballs have never worked around this farm.
d-con, or like poison has worked. though, it never resolves the problem. and it is a constant battle.
a big thing for me, has been removing "drawers" of all types out of the work shop. and going with everything on shelves. or if hand tools (screw drivers, wrenches, drill bits, etc... hanging them up on nails. never use any sort of large box or container on the shelves. i will still use like the plastic coffee containers, and small boxes of like size. to keep nails, screws in, and other small things. and the couple containers i do have, and large box i do have, is made of metal, with doors that shut very nice and tight all the way around. also keeping the shelving so it is only at max 2 feet wide. keeps me from junk piling stuff in place. and if i do, the pile is small enough, that rodents do not bother it.
i have re-done how i stack scrap lumber, and other things. and made min 2 to 3 feet wide stalls about 3 feet deep. and as high as the spot in the shed as they can go. it helps me keep things organized, but at same time. it helps keep potential "nesting sites" down to min.
i do have dogs, and there is always a cat, either someones idea of saving there cat by dropping it off in the country (by the time i see most of the cats they are almost dead if not dead already due to they do not know how to hunt due to they are house cats) regardless d-con is normally placed in high spots. when i do find the dead mice or rat. around here, they are normally in enclosed spaces, were wind and cold can be minimized.
as far as mice in tractors to vehicles, to lawn mowers, and other machinery. heck even the outside gas grill. those little freaking varmints get into every place. to be honest found it better to not place tarps over anything. and if it needs protected it is in the shed to keep direct wind rain / snow off of it. beyond that. a tarp to me = a breading ground for mice nests.
example a wood pile for fire place, prefer a lean to shed, (1 side and just a roof if any sides what so ever, and just a tarp around the sides. less hassle wrapping the wood up, at same time, if a mouse or rat wants to build a nest, it going to have to build one in very middle of the stacked pile. and it will most likely be very cold. spot for the varmint.
things are a lot better and mice and rats are well under control vs years ago here on the farm. about the best advice besides keeping up with eradication of the mice and rats. is to keep things cleaned up. and do not become a pack rat yourself, and if you do, then become a organized pack rat. and keep min amount of things in boxes and drawers. and rest of stuff on shelving, and not piled so tight that it might invite a varmint to make a nest.