Have you considered keeping some tick predators (e.g. chickens)?
If you find a possum in your yard, leave ‘em be and count yourself lucky.
We also have a lot of deer here and they carry ticks that get huge on them, so they're spreading them around wherever they go. We're surrounded on 3 sides by Army Corp land that's forest and filled with critters that spread them around.
I'd never seen a Golden Eagle before and it is by far the biggest bird I've ever seen. They're huge! I yelled at it and waved my arms (trying to look big) and it finally let go and flew off.