The taxes are less than buying the farm outright so it would just be a very cheap buyout. I do not see the problem, you can get finance for that in civilized nations. It's not easy but neither is buying a farm normally.
Inheritance, even with normal tax, is a cheap way of keeping money in the family and keeping rich people rich. It is not based on merit, capabilities or need and serves no purpose in a society based on improving the lives of the entire population. (Which you can argue is not what [country with low inheritance tax] is)
Here in the Netherlands the (once setup as) farmers coop bank is notorious for not doing that, they heavily favour bigco and business models that capture subsidies effectively (which usually means scaling one part to ridiculous proportions).
1. Continue operations of the family farm, assuming you can come up with the money to cover taxes.
2. Sell the farm to Big Farm, Inc., get a $5M check and forget about it, regardless of the consequences that means to your customers.