The maximum course size that you can set up with SwiftPaws for home is limited by the motor's capabilities. We say "around 200-300 feet" because that's typically the size course you'll be able to set up.
Under ideal conditions (indoors, or on level terrain, no tall grass etc.) you'll probably be able to go a little longer. Under less than ideal conditions that put tension or drag on the system (uneven terrain, tall grass etc.) you might have to make a smaller course.