Southern Swiss Alps
 

I will be driving from Stresa, Italy to visit Zermatt, Wengen and Murren end of May and have 4 full days. Can you recommend where to stay with car and we will visit these spots via train since I read they are carless.
Was considering Brig, liked the idea of thermal baths, thoughts?

Brig is nice but a long drive from Zermatt and longer from Jungfrau towns. Consider ditching car in Italy and taking trains right to those towns. With car Lauterbrunnen and Grindelwald make good bases reachable by car. But you must take trains or cables to go above those towns - for lots on Swiss trains check www.sbb.ch; BETS-European Rail Experts and www.ricksteves.com. At Zermatt you can park a few miles away at Tasch and take shuttle trains to Zermatt.

The obvious transport hub is Visp:
1 hr 40 min by train to Grindelwald,
1 hr 05 min by train to Zermatt,
50 min by bus to Saas Fee,
45 min by train and rope railway to Crans-Montana,
1 hr by train and cableway to Moosfluh/Aletsch Glacier
1 hr by train and bus to thermal spa Leukerbad.
10 min by bus to thermal spa Brigerbad,
1 hr by train and bus to thermal spa Saillon-les.Bains,
1 hr 05 min by train and bus to thermal spa Ovronnaz,
25 min by train and short walk to thermal spa Moerel Breiten.

........and 1 hr 05 min by train from Stresa

I wouldn't stay in Visp if you have time for a few days in Grindelwald and Zermatt areas - but for one base for one day trip to each yeah.

Visp may be a transport hub but honestly it is not a very nice town. Brig is far nicer with far less traffic. Anyway if you plan to drive and are prepared to put your car in garages in Täsch and Lauterbrunnen you can visit Zermatt, Wengen and Mürren. End of may the Grimsel pass is probably not open (though it is worth checking to see if it is...) so your route would be:
Stresa/Gondo/Visp/Tàsch and park in the Matterhorn terminal for the train to Zermatt. Parking is about 15frs/24 hrs. Train round trip is 16frs. or so

Then back to Täsch and collect the car. Drive down to Visp. IF the Grimsel is open, drive up to Gletsch (via Fiesch) and over the pass and then down to the Interlaken area, up to Wilderswil and on to Lauterbrunnen. If not - drive to Gampel and up to Goppenstein. Put the car on the train there. You get off at Kandersteg and then drive down to Spiez, and on to Wilderswil etc. Car train costs about 30frs. one way.

You probably should buy a vignette for our autoroutes at Gondo when you cross into Switzerland. Cost is 40frs and that is the only toll you will pay. Without it you will have to avoid a short autoroute section between the bottom of the Simplon pass and Visp but also a longer and more useful section between Spiez and Interlaken. If you do not have it, do not follow any route signposted in green and white. Only take blue and white ones.

There is no doubt hat Brig is the nicer place, but only the old city south of the railway station.

OP should just drive to Tasch for Zermatt and Lauterbrunnen or Grindelwald for Jungfrau and stay there IF they are spending more than a day and a brief day just lets you see it briefly -instead of doing both I'd settle for 2 nights or more in one of other.

Zermatt - Tasch is basically a parking lot for cars which can go no farther - Zermatt is much nicer. the train to Zermatt is awesomely scenic - one of most scenic in Switzerland.

The old village of Täsch is quite pretty but the hotels in Täsch are right next to the station - for a good reason! Everyone who stays in Täsch wants to go to Zermatt. Zermatt has a "buzz" about it and it is a shame not to stay there. You won't save all that much money either by staying in Täsch. Use www.zermatt.ch to search and book your Zermatt hotel. This is the Tourist Office website and will show ALL hotels with availability for the date in question. Be careful to tick Zermatt - it also offers options in Täsch and Randa (which is even further away...)

Most people stay at Taesch for the night only.
You may easily have dinner at Riffelberg and leave this place by train at 20.20 in order to arrive at Taesch at 21.07,
Taesch bound shuttle trains leave Zermatt every 20 minutes until 22.30. During weekends in high season, the shuttles run every hr between 23.30 and 5.30am and then again every 20 minutes.