The start at preston Park is easily walkable from either Preston Park station or London Road station.
For this reason, (assuming you'll be getting to the start by train), look for accommodation either north or east of Brighton. That way you won't have to change trains.
Anyone staying west of Brighton (ie Worthing) will have to change at Brighton - unless there are buses laid on.
Lewes is a wonderfully quaint old town with some seriously decent pubs. trains stop at London Road too. Only downside of course is that Sweder lives there.
Northwards look at Burgess Hill or surrounding. trains to Brighton stop at Preston Park.