Apart from boating and walking there are other attractions in the Lake District.
While out today I picked up several publications. Some are listed below. All of these can be googled for more information.
Brantwood, Coniston (John Ruskin's Home)
Brockhole (between Ambleside and Windermere)- this is the Lake District National Park Visitor Centre, but is also a less well known Arts and Crafts Villa.
Dalemain Mansion, by Ullswater-also the home of an annual Marmalade festival which is much more fun than it might sound
Holker Hall and Gardens, near Grange over Sands- home of the Cavendish family
Hutton in the Forest- the home of Lord and Lady Inglewood, originally built as a stronghold against the marauding Scots
Lakeland Motor Museum-at Backbarrow, south end of Windermere
Levens Hall and Gardens- home of the Bagot family, well known for it's topiary
Mirehouse and Gardens- just outside Keswick- a house with connections to Tennyson, Southey and Thomas Carlyle
Muncaster Castle, gardens and Hawk and Owl Centre- especially known for it's Himalyan gardens and rhododendrons, you can also stay in some of the outbuildings there;
As part of the National Garden Scheme there are various private gardens open on certain dates around the year, to raise money for Charity
On Ullswater, as well as the Lake Steamers, there is the Glenridding Sailing Centre- where you, and children as young as 6, can learn to sail, to canoe, and to Kayak
Keswick Museum this year marks it's 125th anniversary on it's current site. As well as the exhibits (some quite quirky) there is a wide range of Children's Activities. The two major exhibitions this year are one on the floods of which Keswick has had many, the second is about the science of John Dalton and Jonathan Otley
There are also a large number of Farmers and Artisans Markets throughout the district- too numerous to list here.