Gondolas dont start till May 25th - Alternate hike ideas

Don't be sad. Perhaps there is a bus as a substitute? You may actually enjoy places more with a smaller crowd.

Yes, just riding the train to Wengen and then hiking from there will probably fulfill your dream. In fact, the area around Wengen itself is much more beautiful, in my opinion, than the hike you were hoping to do (which I did in September). You will see green hills all around. The tourist office there will set you up with a brochure offering many hikes.

There is a poster on this site who lives in Wengen and hopefully s/he will weigh in.

You can go up at Mürren and walk back toward Grütschalp for great views. You will have to turn around and walk back because I understand from another person that posts here that the train along the cliff between Grütschalp and Mürren is closed in May to replace equipment, but it would be a nice out-and-back with great views.

You can ride the train to Kleine Scheidegg and if the trail to Männlichen isn’t covered in snow, you can hike partway and return to KS.

Last May we went up at Beatenberg https://www.myswitzerland.com/en-us/destinations/beatenberg/ and walked along the ridge. Lots of fun watching the paragliders take off and the restaurant has a great view for lunch. Our walk was a bit short as we did hit snow on the trail even in mid-May, but it was warm enough to dine outdoors.

Walking in the valley from Stechelberg to Lauterbrunnen is very scenic and easy. Or walk the other direction. You can take a bus either way so it is a one way 3 mile walk.

Janet, thanks for mentioning Wengen! So many nice walks there. I really like the Mönchblick and the Staubachbänklii. Each is about an hour roundtrip and there are several others. Stop in the Wengen tourist office for a map.

Take the train from Wengen to Kleine Scheidegg and then walk to Wengernalp before taking the train back to Wengen. That trail has amazing views that are somewhat a continuation of the Panorama Hike, so you'll get a similar vibe.

The cable car/train between Lauterbrunnen/Grutschalp/Murren will be closed for your dates but you could do something like this....
Wengen > Lauterbrunnen > Walk Lauterbrunnen Valley to Stechelberg > ride the cable cars all the way up to the Schilthorn for epic views > ride the cable cars back down to Murren to walk around the village > walk down to Gimmelwald > walk amidst the farms through Gimmelwald > cable car back down to Stechelberg and bus or walk back to Lauterbrunnen before returning to Wengen

You'll still find amazing alpine moments even without the Panorama Hike.

Wengen > Lauterbrunnen

Only if your knees and hips are in excellent form! It’s a brutal (IMO) downhill.

I do love the Kleine Scheidegg to Wengernalp walk, though. Good idea.

Even if the cable car had been operating you would not have been able to do the panorama walk to Kleine Scheidegg as that does not open till mid June.
Such are the facts in a place that has distinctive seasons. You are after the end of the Winter season and before the start of the Summer.
A nice walk with good views however is to walk back from Kleine Scheidegg to Wengernalp. The trains are operating. Do this in the afternoon and you might even see some avalanches.