There is actually a function that sends a task force around the system at pretty much random - its called Task force training. While this is on the task forces gets sent to random locations at a random speed, and when it reaches it a new location is generated. The problem with this is that it wont refuel automatically (conditionals dont work on Task Force Training)
If on the other hand you want the TF to follow a prescribed path, use cyclical orders eg Go to Mars, Go to Jupiter, go to Venus, Go to Earth, Refuel & Resupply and then select the Repeat Orders checkbox, and the TF will follow this path continually.