Sarah is planning a road trip across three cities. She travels from City A to City B, which is 120 miles away, and then from City B to City C, which is 180 miles away. On her way back, she takes the same route in reverse. If her car consumes fuel at a rate of 0.05 gallons per mile and the cost of fuel is $3.50 per gallon, how much will she spend on fuel for the entire trip? Let's think step by step and output the final answer within \boxed{}.
user