We regularly stay at Matson Ground cottages in Bowness. They are situated about half a mile up from the town, up a small lane and you are quite remote up there. Looks out over hills/fields.
Great as a base for all sorts!
It's easy to walk into Bowness/Windermere for sightseeing and boat rides. Booths supermarket at Windermere sells lovely food for self catering.
If you don't mind a bit of a drive Grizedale forest for walking trails and other activities, aira force waterfall, Eskdale Mill are all good.
Keswick is good - nice town centre but also plenty of walks from there. Latrigg is a good one -quite a climb but great view from the top! Nice lake near the theatre too. Mary Mount hotel not far from Keswick is good for food.
Grasmere is a lovely village - nice cafe there.
Brockholes activities centre for watersports/go ape etc.
Walks - loads, have a look online/buy a book on amazon but take an OS Map too.
Motor museum at Newby Bridge is good - you can get the steam train from Lakeside or just drive there. Bobbin mill at Newby Bridge is also good -really informative guides.
Coniston is nice -can walk up to the tarn and around. Or get the gondola part of the way and walk the rest.
Threkeld quarry is quite interesting too.
If you want a nice meal, the sun at crook is lovely.
I love the Lakes-we go every year (usually Autumn/Winter) and never tire of it.