In your shoes, I'd ride out west to Ascot (or thereabouts) and back. I've got a loop around Farnborough that you can have if you want but you might want to make up your own bit that doesn't actually go to Farnborough itself because it's horrible, but it's very easy going out in that direction if you keep away from the Chilterns.
Kent is hillier than Surrey.
In your shoes, I'd ride out west to Ascot (or thereabouts) and back. I've got a loop around Farnborough that you can have if you want but you might want to make up your own bit that doesn't actually go to Farnborough itself because it's horrible, but it's very easy going out in that direction if you keep away from the Chilterns.