Original sentence: A one-way trip (rim-to-rim) takes place in around five hours, or a round-trip (the rim-to-rim-to-rim or "doublecross") in around eleven hours.The canyon is extremely popular with endurance athletes who regularly run across it
Edited sentence: Park service forecasts are rarely accurate and often inflate adverse conditions as a deterrent to canyon hikers.The Canyon is extremely popular with endurance athletes who regularly run across it (the rim-to-rim) in around five hours, or run from one side to the other and back again (the rim-to-rim-to-rim or "doublecross") in around 11 hours