If coming from the south, many coastal towns have direct trains to Gatwick

https://telegra.ph/Gatwick-Airport-Journey-Planner-Tools-and-Tips-to-Pick-the-Right-Route-08-21-3

If coming from the south, many coastal towns have direct trains to Gatwick. Check Southern and Thameslink routes from places like Worthing, Lewes, and Eastbourne.