I've been to Rye, a lovely old town with cobbled streets and timbered buildings. Camber Sands is well known for, as its name suggests the sands, extensive, quite a novelty in Sussex mostly pebbles apart from West Wittering right at the other end of Sussex. Winchelsea is a pretty village nearby. Other places to visit fairly close would be Bodiam Castle, NT and if you venture into Kent, Rye is on the outer reaches of Sussex bordering Kent, Tenterden is a very pretty town a few miles away and the surrounding countryside between Rye and that part of Kent is lovely.
Have a great time.