Hi Ashley, and welcome to MySwissAlps!
Is this trip for next year? I’m assuming it is!
>>> Mostly interested in going on hikes and sightseeing.
It’s a bit early for higher altitude hikes in the Jungfrau Region, which typically don’t open until mid-June. There will be some lower altitude walks you can do though.
>>> 20th: Schynige platte + Lakes Thun and Brienz
The Schynige Platte railway doesn’t reopen until 15 June 2024. The date for next year will be similar.
Boats will be operating on the Lake Thun (2 services per day in each direction) and Lake Brienz (4 services per day in each direction), so you will need to plan carefully to fit both in.
https://www.myswissalps.com/activity/boat-lake-thun/
https://www.myswissalps.com/activity/boat-lake-brienz/
>>> 21st: Grindelwald
The gondola to First will be operating.
https://www.myswissalps.com/activity/grindelwald-first/
>>> 22nd: Lauterbrunnen + Harder Kulm
The Trümmelbach Falls reopens in early April, so you should be able to visit them.
https://www.truemmelbachfaelle.ch/e/
You could do a walk along the Lauterbrunnen Valley to Stechelberg.
https://www.myswissalps.com/blog/hike-lauterbrunnen-stechelberg/
You might also be able to do the walk from Grütschalp to Mürren, but trail conditions might not be ideal (e.g. snowy and/or muddy patches)
https://www.myswissalps.com/blog/hike-grutschalp-murren/
The funicular to Harder Kulm will be operating
https://www.myswissalps.com/activity/harder-kulm/
>>> 23rd: Jungfraujoch + Interlaken (explore the city before leaving)
You will be able to go to the Jungfraujoch, but don’t buy your ticket until the day before at the earliest – or better still on the day – after checking that the weather will be clear.
https://www.myswissalps.com/activity/jungfraujoch/
You can check the weather forecast here:
https://www.jungfrau.ch/de-ch/live/wetter/
A webcam for checking whether there are clear views at the Jungfraujoch are here:
https://www.jungfrau.ch/de-ch/live/webcams/
Info about Interlaken is here:
https://www.myswissalps.com/town/interlaken/
Hope this helps!
Alpenrose