You and me both mate. Those little bastards are not tolerable inside vehicle or house envelopes.
They somehow got into the attic and soffit space in the house we built. I instantly recognized the sound of the little feet on the aluminum soffits, and told my wife that squirrel war was on. She had been warned earlier but did not share my intolerance, so pre-emtive strikes would have, shall we say, stressed relations.
Long story short, I went over that house envelope from end to end, side to side, and dirt to roof top and I could not figure out how the little bastards were getting in there. After about a week of head scratching, I figured it out - the little fuckers had chewed through the metal screen on the inside of the older style roof vents. The damage was invisible until I hole sawed inspection holes in the side of the vent assembly. Every vent in the house had been breached. With determination and time, I trapped the buggers and sealed up the vents with hardware cloth. Since then, the roof has been re-shingled, and the new ridge vents are squirrel proof.
The little bastards also built a nest inside the air cleaner of my Tacoma years back. I only discovered the problem when an engine light came on and the Toyota tech figured out what was up.
A now departed friend of ours had two new Toyota Rav4 vehicles burned to the ground due to packrat nests on the exhaust. The second one burned about six feet from her wooden porch steps. It was a miracle that the house didn't burn down too. The insurance company said that vehicle fires due to rodent intrusion was actually pretty common.
And then there are the mice... Rodents can be a right pain in the ass.