I've based at Keswick, but then I drive to places like Buttermere and Borrowdale (there will be buses though as these are popular destinations and Borrowdale is just down the valley from Keswick) as well as Derwentwater itself. I would suggest a walk around the lake at Buttermere - takes a few hours and lots of vantage points for photography, waterfalls, lake views - the view from Buttermere village across the lake to Feetwood Pike is a good one if the weather is playing fair, as is the view from the shore at Keswick looking towards Borrowdale.
Suggest you get a book or three from the library. FWIW, there are a couple of Lake District shots in my gallery here.
Are you aware of this (http://www.apug.org/forums/forum137/20524-apug-uk-spring-2006-gathering.html) thread?