I wouldn't place it in that location. Some people will trespass; it's inevitable. And I personally don't like to provide the temptation.
As to distance, I'll happily walk many kilometers (a measure of distance outside the USA) for a single cache; I think my record is 19km one-way and uphill.
The primary route that will be most obvious to the hardened cacher will be the BRIDLEWAY that i use... The farm entrance has a coded gate to stop vehicular access.