This game is more fun than it has any right to be. I haven't played much single-player, though, and I suspect farming with friends is part of the charm.
Although I haven't done hardly any farming at all, really. I hire workers to do the work, and I just supervise and make the money.
The basic game is interesting, but it's the mods that really make it shine, IMO.
Worth checking out if it goes on sale this Summer.