We use Sierra Pest Control for bugs and our free range chickens help. I would get a cat. We use to have an issue with chipmunks getting in. Once we got a cat that all stopped. I suppose that probably wouldn’t work for a cabin if you lived out of the area.
We use Clark for the spiders, does an excellent job.
Not to sure about the squirrels. My neighbor contacted John DeMetris *(827) 952-2443, John was able, after a couple of attempts to find all the entrances.