Heritage Open Days are on all week, so this is the one to plan indoors and out. Keep the walk for a dry day.
Mid September brings shorter days and cooler mornings in the Lakes, with the bracken starting to turn. Check the MWIS Lake District forecast before setting off, and take a waterproof either way.
Heritage Open Days run until Sunday, which means houses and halls that are normally shut, or normally cost money, have a few free tours on. Details below come from the organisers' listings, so check anything you plan to travel for.
Start: Smardale car park, Smardale Nature Reserve, near Kirkby Stephen CA17 4HG
Cumbria Wildlife Trust looks after this stretch of disused railway, and the payoff is a big Victorian stone viaduct with views over open rolling country on one side and a steep wooded gill on the other. Autumn brings Scotch argus butterflies, devil's-bit scabious and later flocks of fieldfare and redwing. A weekday in the Eden Valley is about as quiet as Cumbria gets.
Public transport is limited and the car park is 1km beyond the railway crossing, down an unsigned turning off the A685 between Ravenstonedale and Kirkby Stephen. Dogs must be on leads. The longer route to Newbiggin-on-Lune is 11.4km return and has wheelchair and pushchair surfacing with benches.
Sedgwick, Kendal LA8 0JZ Free (Heritage Open Days), Adults
A guided walk to the ruins of the New Sedgwick gunpowder works on the Sizergh estate. Booking is essential on 015395 69818, the paths are rough and unsuitable for wheelchairs, and stout footwear is required. One listing site gives this date, so ring to confirm. Details and booking
Grounds open 8am to 8pm daily, café 9.30am to 4.30pm
Low Wray, Ambleside LA22 0JA Parking £7 for 2 hours at the time of writing, Adults
The castle itself is closed for refurbishment at the time of writing, but the grounds are open, and there's a free outdoor photography exhibition, Pages from the Potter Family Album, by Beatrix Potter's father. Blue Badge parking and all-terrain scooters are available, and the 505 bus stops nearby. Details and booking
Hop-on hop-off cruises with several jetties. The site says there's a limited launch service at the moment, so check before you plan a day around it. Details and booking
Allan Bank, Grasmere LA22 9QB Free tour (Heritage Open Days), house admission may apply, Adults
A tour of the house with its conservator, listed in the Heritage Open Days programme with no booking. There's no on-site parking, so use the village car parks, and the accessible route round the grounds is 1.9km. Details and booking
Brougham, Penrith CA10 2DE Free (Heritage Open Days), Adults
A guided tour of the restored hall near Penrith. The listing says it isn't wheelchair friendly. The workshops on site are open from 10am to 4pm, so you can make an afternoon of it. Details and booking
Theatre by the Lake, Keswick CA12 5DJ See the box office, Adults
The theatre's own production, which runs until Saturday 10 October. There are 2pm matinees on selected dates, plus captioned, relaxed, BSL and audio-described performances. Ring the box office on 017687 74411. Details and booking
An open exhibition of young artists' work that runs through to the end of October. Good for a Thursday in Kendal alongside the town's other heritage events. Details and booking
Ravenglass, on the west coast See the website, Adults
The line has nine stations and heritage steam engines, and two of the stations have licensed cafés. I'd go on a weekday when the trains are less full. Details and booking
Rain-proof
Tip. Heritage Open Days listings change, and many tours are run by volunteers, so check the venue's page the day before. Ring first if the listing says booking is essential.