I got it pretty damn clean with no mod help, but also I played without tessellation enabled in the graphics settings which removes all of the finer bumps in the terrain. Saves a few frames too.

I would be kind of careful when putting down the first two rows of crops, and after that I just kept a rhythm as I got the hang of working with the offset camera.

Another method would be to have two different alignments of rows going. So every row is offset by 50% from the last, but still aligned with the row before last. You can pack each line quite tightly together this way and also have an additional diagonal axis to use as a guide. Kind of like:

X-------X-------X---
----X-------X-------X
X-------X-------X---
----X-------X-------X
X-------X-------X---
----X-------X-------X
X-------X-------X---
----X-------X-------X
X-------X-------X---
----X-------X-------X

And so on. The diagram doesn't quite do it justice because the size of the characters makes it difficult to align but you probably get the idea.