Our farm insurance has $20 million public liability, product liability, asset protection, and two farm utes on the same policy. It's around $450/month with RACV. I'm just starting to investigate what I would get with RuralCo though as I reckon RACV is a silly choice - not their main game.
The policy covers visitors and volunteers, but not staff, as that's under our Workcover policy. It's prudent to outline the risks to people, and if you're really worried you can even get them to sign a thing that says they've had all of the obvious risks identified for them (we don't do this).