Grew up and moved from California. Don't miss In n Out. When I visit home, I'm so surprised that there's no Steak n Shake. The double steakburger with ($4 for burger and fries) is pretty great (although it always needs a little salt, which I add). I think it's easily the best fast food burger.
Every now and then I get one that isn't that great, so I would be somewhat disappointed if I tried it for the first time that day. But most of the time it's a really good burger.
As BYUMizzou said, use the drive thru. I always do.
Also, I always get the double steakburger with cheese, so I can't comment on their other offerings.