The flat cycle route up Langdale is much improved. Best between Skelwith Bridge and Elterwater but my dad thought that you could get all the way to the Old Dungeon Ghyl on it now. Or walk you can walk from Skelwith Bridge to Elterwater/. There ducks at he one point where the path is next to Elterwater. Get a bus timetable so some of you can do the walk one way
I think the first section up the Langadel valley is on road so not ideal as its narrow and busy
Good cafes in Skelwith Bridge (huge cake and posh) or Chapel Style (above the Co-op community run)
Boat trips on most lakes. Maybe get the boat from Ambelside to Bowness. Wander round their and see the swans and boat back
Rowing boat rental on Grasmere, Coniston and Derwentwater
Sculpture trail and Play ground at Grizedale. Plus great bike rides on smooth wide trails. Do at least one leg of the car journey on the chain ferry from Bowness
Far end of the lake for the Aquarium of the lakes and steam train. Could travel there by boat
The back road to Rydal water is mainly traffic free (no through traffic). It starts behind Rothay park. The Park is great, the “beach” at Rydal water is great for sticks and stones in the lake type play
The West shore of Windermere has a great family friendly Bridleway
In general I advise not spending all week driving to the other end of the lakes. The exception being driving to do Catbells which ss a good family peak, if one of you can carry the 2 year old
Your succes criteria is staying out of The Beatrix Potter Experience
PS water fall at Colwith Force. Weird fallen tree covered in coins hammered in