Long way ahead I know but if anyone is staying over at Gatwick the night before there is currently a deal for £75 at the Hilton hotel which is connected to the terminal.
I've just booked through Expedia but same deal is on holiday extras.
There are cheaper hotels in the area but by the time you've paid for transfers it doesn't save anything so may aswell have the convenience of been next to the terminal.
Just train tickets to sort now, but they wont be available yet.