Hi UStravelers -
Thanks for the dates. You are in good shape. At that time the Jungfrau Region will be starting to open up for Spring, and mountain cableways will almost surely be operating. If I were doing it myself...and it is definitely worthwhile even when services are limited....I'd move the Jungfrau region to the end of my stay. A few days at the end of May can make a noticeable difference in the region.
Here are some specifics, perhaps more than you need, which are simply to give a general feeling of how the Region wakes up from Winter in May and early June. Typically, the cableway from Wengen to Männlichen, and many other cableways around the region , close for lack of skiable snow or hikable high trails on the first weekend in April for maintenance. They begin Summer operation in late May. In 2017 it was May 20th. Don't recall 2018. In 2019 it opened earlier than usual, on May 11th.
www.maennlichen.ch/en/ summer/information/tim etable.html
Whether that was due to warmer weather (snow melted earlier) or to add capacity because access from the other side ( from Grindelwald) was constrained due to construction, I'm not sure. That construction will be complete next Spring, so it won't be an issue. You won't be able to get an exact timetable until after December 15th this year, when the 202o timetable will become available. If I had to bet, I'd bet that that really nice cableway will run starting May 23rd. And, if therer is a lot of snowpack, it could even be later.
I was concerned that you would get to the Jungfrau area and not be able to experience the best parts, as noted in my earlier post. In fact, the trail I mentioned won't be open till mid-June, but you could still ride up to Männlichen for the view and a bite to eat. Other mountain access should be available, too.
Mürren is a village requiring year round access so there are two routes which close for different maintenance times, one of which often extends into early May. Access to Schilthorn, going up from Mürren, became available on April 27th in 2019.
The cog-railway that serves Kleine Scheidegg (and the Jungfraujoch) runs all year.
This map gives a good impression of the area; Train lines pop up when you zoom in fare enough:
Your dates not run into any problems with sightseeing by public transport. However, you won't be able to access even easy walks above about 1800 to 2000 meters. They'll either be snow covered or unsafe because of potential snowslides.
Interlaken itself does not have a problem with altitude. It is at low altitude and the snow will be gone by then. However, it is not much of a destination for tourism. It is basically a gateway town and commercial center for the rest of the Jungfrau Region, where the best scenery is.
More details on this page, comparing the villages. Scroll down, on the right:
The altitude effects that I have expressed concern about have to do with weather, especially seasonal weather, not altitude sickness.
Most conventional passenger jets set the cabin pressure at an equivalent of around 7,500 to 8,000 feet above sea level. That is about 2300 to 2440 meters altitude.
As a simple general observation, and I'm not a physician, if you don't feel discomfort from that "altitude" on your many hour long flight over, you likely won't be bothered at any altitudes of that range in Switzerland. Just for examples, Interlaken is at about 560 meters, and Wengen at about 1270. Männlichen is at 2230 meters, comparable to an airliner.
If you have impaired breathing...for example, emphysema, you'd better check with your doctor. Even with normal health, you will likely find that exertion at those altitudes...climbing steep ascents for even a few meters, for example, may cause you to walk slowly or pause to catch your breath. That is most noticeable on your first days at altitude.
The peak of Stanserhorn is at 1900 meters. Honegg is a around 950 meters. You are not likely to notice that altitude at Honegg , in my opinion.
Hammetschwand Lift -I'm certainly not suggesting that you walk up there from the backside, which could make sense from Honegg, if the Felsenweg and the lift are not open.
The lift usually opens sometime in May. I'm almost certain that it will be open when you are there.
<<"Perhaps Lucerne would be better for us as my husband is not a hiker, loves to "ride" and likes walking and exploring towns, but we would like to take a cable car up the mountain.">>
Pilatus will be open and is close by. Probably the cog-rail will be running. The cableway runs all year except for maintenance. Titlis (3032 meters) is accessible as a day trip, via Engelberg. There is snow up there all year long.
Luzern has really nice variety. The Jungfrau Region is spectacular.