Someone was hurt riding on my land. Am I liable?
Arizona limits the duty a landowner owes to recreational users who are not charged a fee, which is a genuine protection. It does not cover a wilful failure to guard against a danger you knew about. And even a good defense costs money, which is what your liability cover pays for.
What if I charge a small amount?
That changes the position materially. Charging can take the arrangement outside the statute and can also make it a business pursuit, which personal policies exclude. If money is involved at all, tell us, because it needs a different arrangement.
Should I post signs or fence the hazards?
Yes. Marking or securing known dangers such as old wells or workings is both sensible and relevant legally, because the protection does not extend to ignoring a danger you were aware of. It is the cheapest risk control available on open land.