casco de estancia

how do you translate casco de estancia?

it means the main house in a farm

And what's wrong with "main house"? Regardless of the term you use, it will not be universal. On different ranches, the name will vary. You may live in "the main house" but your neighbor may live in the "ranch house". Different expressions, same meaning.

I am heading to the main house.
I need to go to the ranch house.
I have to return to the compound
I'll see you at the big house.

Ok, you´re right... sometimes we tend to look for a more complex word, when in fact it can be translated with a simpler word...

I would say "buscarle la quinta pata al gato".

thanks!