No one has posted here for three months, are we all retired from gardening?
Today I have some help cleaning out a pack rat nest. It was well hidden in a low-growing Chinese Juniper. There was a big pile of wood chips, some dried prickly pear pads, plus an old plastic cup and a couple of straws.
Does anyone have any suggestions for trapping them? What works best for bait? I've had thousands of dollars of damage to my car, and am no longer at all sympathetic to their cause.

I wish I knew the answer. We have 10 wooded acres and probably at least 50 of these rats. They have their wood stack nests everywhere. We had the wiring eaten on our travel trailer. The brake and turn lights didn't work and had to be repaired. We have so many that I don't think we could ever trap all of them. Fortunately our vehicles are in the garage.

MsDoe pack rats are a problem here as well. I use the non kill traps putting carrots or lettuce in them. After they are caught we used to release them out in the desert with a pile of food for them.

Fortunately I have a garage so vehicles are safe.

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.

Sounds like I'm not the only one with this problem! Thanks for all the suggestions.
I have surrounded the car with snap traps, poison bait boxes, live traps and an electronic trap. Peanut butter has been my most successful bait, but I think I'll try some apple slices just for variety. I also have a few mouse traps out. I've stopped chasing off the neighbor's cats.
I keep the hood up on the car, and the light on at night. I've destroyed any nests I find.
I think my downfall is feeding the wild birds. I keep the birdseed in a metal trash can, and now use a squirrel baffle on the pole the feeder's on, but some seed still ends up on the ground.
Here's what my carport looks like:

Out. neighbor has a strong of lights under their car because of the pack rats.