Hunted middle of the winter at a farm. My son was there with a small excavator, found a nice target. The ground was so frozen he could not dig it up, I went home.
Also there is a good size spot between two houses that looks abandoned, been that way for years. My son (different one) says put a vest on and have at it, Maybe I should but I most likely won't.
You should check with Boston scientific robotics, maybe they can help you out. They could make a metal detecting mule, take you, your stuff, and lunch. Your welcome, let me know how that goes.