The working line GSDs are bred to be worked which for most people means in a sport, like Schutzhund, tracking, agilility, herding. That is why many working line breeders specify "working homes preferred". The majority are high energy dogs that need that outlet and a lot of exercise. Training in obedience isn't enough - they need to be "worked" in the exercises even after they have learned them.
It's true that working lines need good exercise and continued training, like all dogs, but that doesn't necessarily mean you have to compete in a sport. Since the OP has 60 acres, just running the property (supervised, of course) could provide enough exercise, and as long as the OP has the time and the wherewithall to train (and continue training), a working-bred GSD could be a good choice.
Many working-line dogs do have an "off" switch, so given good exercise and training, can settle nicely in the home and be a great companion. I have a working-line GSD who mostly holds her bed down in the house; once outdoors, her drive and energy bursts forth and she could go all day if I let her. She is 11 years old now, and has calmed with maturity, but has pretty much always been good in the house.
It seems that most working-line GSDs are sable, so if the OP wants a sable dog it should be no problem. In fact, if you want any other color, it's becoming something you have to look for.