These are two less well known National Trust sites to see in the Lake District (opening dates don't tend to be announced months in advance, so you just have to keep an eye out and be lucky)-
Derwent Island (in Derwentwater, Keswick)- open 5 days a year, although not open at all in 2023 due to staff shortages. You have to canoe a short way from the shore to the Island- in times past the NT used to hire a Lake launch but those days are gone
Force Crag Mine, Braithwaite, near Keswick- opening days are only a few a year and are unpredictable- this year they are 16 July and 10 September. This year for the first time transport is to be provided from Braithwaite. In the past you have had to walk the 2 miles up the valley. This was the last working mineral mine in the Lake District being worked from 1578 to 1991.