While in Phoenix over the winter I stopped at a Ford dealer for an oil change on my F150 Ecoboost. During check out, after the 90 minute job, they mumbled that I was due for a Brake System Flush, a Fu...
Fuel flush is bogus. Get some fuel treatment at pep boys if you feel obligated.
Coolant replacement go by the book (100k) and you should never need a 'flush'. Use distilled water only to dilute new coolant or to rinse out the old.
Brake fluid I recommend when you get new pads or shoes. Or by the book if in a humid climate. I do my own with a $50 pressure bleeder. Motive Products.
Transmission be sure to use the severe duty schedule since you are towing.