This is a lot of what i see. I'm escaping the city to the sticks. Surrounded by farms where a lot of people already shoot. I think I'm good there, but will definitely make friendly with the neighbor and keep the shooting to reasonable hours.
nothing behind it for a long ways
There is no structures for almost a mile in the direction i selected, it was selected for just that reason. But there are pastures.
Build it twice as high as you think it should be
Well I was going to do 8 ft berm with 2 more feet of wooden "fencing" at the top. I think 20ft might be a bit much.
I don't know if the sheriff idea is a good one or not. I sounds reasonable, but at the same time if you ask they could try to say "no".
This guy obviously does a lot of training.