"Land in the dirt, you won't get hurt" has, so far, worked well for me.

Farmers don't get worked up about crop damage when it's not even an inch high.

With private strips, width can be a deal/glider breaker. I passed up one in the book because the stated width looked a tight squeeze. And I once saw the green (corn) stains on the tips of an 18m self launcher. The owner had the look of a narrow escape on him. The private strips I have used were known to my local club as wide enough for gliders. The owners have been hospitable and happy to talk airplanes. There's the rare one that won't allow aerotow retrieve because of liability considerations.

You can compare the width to power pole spacing.

No matter how hard you study the local fields and airports, the day will likely come when you have to evaluate fields from the air. It's been recommended for aspiring XC pilots to evaluate possible fields from the air and drive over for a look.