MsDoe, we never tire of gardening, but we do tire of the pests! We had the same trouble under the floor boards of our chicken coop. Ever since we rehomed the chickens and put down a new floor, their presence has dropped drastically. I recommend rat traps baited with peanut butter. We use the Tom Cat brand (I think). They are plastic traps that can be set with a squeeze without worry of snapping your fingers.
Prevention seems to be the best medicine, so clearing up storage areas and pet foods (or livestock feed) will help a great deal. We still get a couple under our house and in the veggie garden each year but the peanut butter is key. We also tie the trap off so any injured rat/squirrel doesn't run off with it although 99% of the time it's quick without suffering.
If you don't have pets, there are various poison kibbles you could scatter but I don't find them as effective as it's a slow process that basically shuts down their kidneys over time. But, they do take it back to their nest and will help long term over a large area. We used the multi-prong approach: Got serious about cleaning-up the space using plastic totes instead of cardboard boxes for all things storage (this is a big deal), eliminated all available livestock feed/water including under floorboards, scattered kibble bait around the perimeter of property and buildings, used gas-style insecticide floggers under crawl space (outbuilding set on wooden platforms instead of slab or ground), and set traps. It was a huge project and a bit expensive, but it was completely effective with only the occasional intrusion now.
If you need a fast and affordable approach, traps with peanut butter is my highest recommendation. We, too, had very costly wiring damage. Stay diligent on checking your traps. Depending on your invasion, you may catch more than one a day. They are destructive. Good luck.
