Hi jltravels, and welcome to MySwissAlps!
>> I will be travelling to Switzerland 28 April - 3 May ... Luzern first ... the Interlaken area but stay in Lauterbrunnen or around.
Here are operational details for mountain transport, boats and some attractions in the Luzern area, Jungfrau Region and area around Interlaken:
Luzern - operating
- Pilatus - the cableway from Kriens to Pilatus Kulm will be operating, so you can go up and back on it; the cogwheel railway from Alpnachstad to Pilatus Kulm reopens early-mid May, so you will be a bit early for it.
- Rigi - all modes of transport operating
- Funicular Kehrsiten-Bürgenstock to Bürgenstock Resort
- Funicular Schwyz to Stoos (the steepest in the world)
Luzern - not operating
- Hammetschwand Lift (based on last year, probably reopens 5 May 2018)
Jungfrau Region and Interlaken area - operating
- Gondola Grindelwald to First
- Cable car to the Schilthorn (reopens 28 April 2018 after maintenance closure)
- Funicular Interlaken to Harder Kulm
Trümmelbach Falls near Lauterbrunnen will be open, as will the Ballenberg Open Air Museum near Brienz. The Aareschlucht (Aare Gorge) near Meiringen will be open, but only from the west entrance/exit, so you will need to retrace your steps to exit.
Jungfrau Region and Interlaken area - not operating
- Cable car Lauterbrunnen to Grütschalp (operates until 29 April; closed for maintenance 30 April to 4 May); you can still get to Mürren via bus from Lauterbrunnen to Stechelberg, then cable car Stechelberg-Gimmelwald-Mürren
- Gondola Grindelwald Grund to Männlichen
- Cable car Wengen to Männlichen
- Funicular Mürren to Allmendhubel
- Train Wilderswil to Schynige Platte
- Train Brienz to the Brienzer Rothorn
>> I would prefer to stay in Gimmelwald, Murren or Wengen, but I don't know if that would be convenient at that time of the year, given the activities that are available.
The ski season will have just finished, and it is too early for hikes at higher altitudes, but the scenery will still be great, and some mountain visits still possible (as detailed above).
Your accommodation and restaurant options will be more limited, as many establishments will take a break as soon as the skiiers are gone. Either Wengen or Lauterbrunnen would probably be your best bet. Interlaken will be livelier, but lacks the stunning scenery of the Jungfrau Region.
>> I've heard the weather can be unpredictable, and it's hard to understand what I can do at that time
That's true of any time of the year. The key thing is really what mountain transport is, or is not, operating. You have plenty of options in Luzern, and some in the Jungfrau Region and Interlaken area.
>> What can I do around Luzern (given the time of year)? How many days should I stay? ... Lauterbrunnen ...
Get ideas from the links below, and check availability of transport above:
>> Would it be easy to get around given activities I can do? (given the time of the year)?
You can get to the villages all year round, one way or another. It's the mountain trips from villages that are affected by seasonal closures.
>> What specific day hikes are recommended around the Interlaken area (given the time of year)?
Search here for valley or lakeside hikes and then check with the experts once you have chosen:
>> I also like quaint and cozy accommodation - with friendly local hosts.
This type of accommodation will probably not be available after the ski season finishes, at least until the hiking season begins in the second half of June. You might have better luck with a larger hotel. There will be some places open, you will just have much less choice.