We're not into touristy things, nor do we want to spend time hiking or watersporting etc. We like ci

My partner has never seen Switzerland and, apart from a couple of days in Geneva recently, it's been forty years since I was there. We have six days to spend en route to Italy and would like to take in some of the highlights, though obviously we can only get a taste.
We're not into touristy things, nor do we want to spend time hiking or watersporting etc. We like cities, museums and architecture but we also like lovely countryside and small villages. I'm keen to see the alps and would like to do a day trip by train somewhere to see them.
I'm guessing because you wrote Thun Lucerne country inns and suites by carlson twice that you mean you will stay 2 days in those places? 1 day for both Vevey Lausanne is just not enough. Perhaps you need to take them out all together and see that area another time. I'd put Gruyeres in instead.
Sorry, I thought you meant Fribourg country inns and suites by carlson in Switzerland. Since you mean Freiburg in Germany, I'm going to revise my suggestion because Gruyeres is too far out of the way. Vevey/Lausanne are also out of the way.
I do think you can do Vevey and Lausanne in one day. Take a nice boat ride between the two or rail. Lausanne is more of a city and Vevey is a town. Could be a great day on Lake Geneva. I would recommend, if there's time, that you go to Chateau country inns and suites by carlson du Chillon while in this area.
Overall for your Itinerary - I personally country inns and suites by carlson would stay in Bern for 3 nights - I love this small, architectually interesting city from which you can do day trips to visit Lake Geneva area (by rail) and can even go to Lucerne for a day.
Then onto the Berner Oberland for the Alps experience - Interlaken is probably easiest for you to stay in. You can do a half day in Thun from there plus funicular, cable car, etc., rides to tops of mountains. Then your last day/night in Lugano.
BTW - If you do stay in Bern, I could recommend the Best Western country inns and suites by carlson Bristol. Go on octopus.com for a great rate. This hotel is simple (seems they all are in Switzerland) and just a few blocks from the railroad country inns and suites by carlson station, so really easy for traveling around.
Sorry, I see you said you were driving. Possible to do what I suggested by car, if there is parking, of course. Don't know if there are parking garages in Bern, but if so you could park the car there and do side trips by rail or contact your hotel about possibility of day trips by car.
Greg, I do know about the drop off fee - in fact we're picking up the car in Amsterdam and doing a longer road trip than I detailed here, and will need it for a week in Arezzo. So we'll pay for the convenience, even if we're not thrilled about it. Thanks for alerting me to it all the same.
kenav, I did investigate staying in Bern but parking does seem a problem. Because of this, we've decided to stay in Spiez for five nights and either train it or drive (prefer train) to Bern and Luzern, and do short car trips to Thun and Vevey. If we find Bern absolutely compelling we can skip Vevey this time and spend two days in Bern.
We just had a lovely trip to Sw in May, and I agree, developing a shortlist is impossible. You simply country inns and suites by carlson cannot find a spot in Sw. that you will not absolutely love. I would echo the above comments to include two nights/one full day in Lucern. That is sort of the penultimate Swiss City. If you are into art, the Rosengart museum country inns and suites by carlson there is highly recommended. Nearby country inns and suites by carlson Mountains are Rigi, Pilatus, and Titlis. country inns and suites by carlson Seeing any one of those is a must. Did not do the Steamer around the lake but wish I did. See my trip report. Happy Trails!