5 nights in March

How long is a piece of string Rach? Is 2 nights in Bern too much for what? If you don't want to ski what do you want to do?

The more relevant info you provide the more relevant responses can be. Without knowing what your interests are it is impossible to say anything relevant about your choices and times.

I could happily spend a week in Bern but a half day might suit you depending on your interests. I would suggest any village in the area but to avoid Interlaken, it hasn't the appeal of any of the villages. What do you want to see/do in Montreux other than visit Chateau Chilon? A half day stop enroute to 2 nights in Geneva might be enough for you, who knows.

How long did you feel was enough time in Lucerne? What did you do/see there that interested you?

I could spend the whole 5 days in Geneva with a day tirp to Montreux and perhaps another on the Golden Panorama train up to Gstaad to see some alpine scenery and enjoy a lunch of roosti with an egg on top. It all depends on your interests Rach and you've told us nothing about them.

Did you realize that Thun is less than 20 min by train from Berne?
5 trains every hour from 5.30am until after midnight.
http://www.myswitzerland.com/en/home.html
http://www.swisstravelsystem.ch/en/

As you plan to stay in Western Switzerland, you max be interested in the following places:
entirely walled medieval town of Murten
http://www.murtentourismus.ch/en/welcome.cfm?
Roman amphitheatre and Roman Museum of Avenches
http://www.avenches.ch/en/page.cfm/siteetmuseeromain
Roman Villa of Vallon
http://www.pro-vallon.ch/allemand/mosaiques/mosaiques.htm
biggest Romanesque church of Switzerland and Monastery of Payerne
Nature Park of Grande Caricaie
http://www.myswitzerland.com/en/destinations/resorts/holiday-destinations-in-switzerland/estavayer-le-lac.html
http://www.bafu.admin.ch/dokumentation/umwelt/00111/00463/00937/index.html?lang=de
Medieval town and spa of Yverdon
http://www.yverdonlesbainsregion.ch/en/Culture_Patrimoine
Roman mosaics of Orbe
http://www.yverdonlesbainsregion.ch/en/orbe_region
Monastery of Romainmotier
http://www.yverdonlesbainsregion.ch/en/romainmotier_region
Castle and Menhirs of Grandson
http://www.yverdonlesbainsregion.ch/en/grandson_region
Menhirs and Dolmen of Onnens
http://www.onnens.ch/textes-1/dolmen/le-dolmen-de-praz-berthoud,38.html
medieval town of Neuchatel with castle, cathedral and many fine museums
http://www.neuchateltourisme.ch/en/decouvertes.html
Biel/Bienne with it's small but fine city center, good museums and a lot to see in the Lake Bienne area
http://www.biel-seeland.ch/en/discoveries/town-and-heritage/biel-bienne.1239.html
Medieval Bueren an der Aare with wooden brige over the Aar river
http://www.bueren.ch/de/inhalte/tourismus/sehenswuerdigkeiten.php?navanchor=1010025
Natural reserve of Altreu and it's storks
http://www.artenschutz.ch/AareAltreu.htm
Medieval town of Solothurn with baroque cathedral and many museums
http://www.solothurn-city.ch/topic2477.html
La Chaux-de-Fonds, capital of watchmaking
http://www.neuchateltourisme.ch/en/decouvertes/museums/clock-making-m-lanbspchaux-de-fonds.1500.html
Gorges of Areuse, Seyon and Taubenloch
historic steamboats on Lake Geneva:
http://www.cgn.ch/horaires/pdf/AffA2-ete-10.pdf
http://www.cgn.ch/eng/flotte
Chillon castle:
http://www.chillon.ch/en/
Gruyeres castle, cheese diary and chocolate factory:
http://www.chateau-gruyeres.ch/e/multimedia/spectacle.html
http://www.la-gruyere.ch/en/navpage-ExcursionsFR-HistSitesFR-120085.html
http://www.lamaisondugruyere.ch/index.php?option=com_content&view=article&id=142&Itemid=56
http://www.lamaisondugruyere.ch/index.php?option=com_content&view=article&id=142&Itemid=56

Zermatt-Gornergrat:
http://www.gornergrat.ch/home/index.php
http://www.klein-matterhorn.ch/photos/
http://www.zermatt.ch/en/index.cfm