>> Can you assist with which trains to take for scenic views. We are traveling (in July) Lucerne to wengen and then later wengen to montreux.
In July, I would make reservations for all sectors of the Golden Pass, i.e. from Luzern to Interlaken Ost, then for all sectors from Interlaken Ost to Montreux. It's not only a peak season for tourists, but there are also school holidays in the Canton of Bern from early July to early August.
>> We will also travel Zurich to luzern; montreux to Geneva; other day trips. If a more scenic route is available, great! How do we know which routes to take to.offer best experience?
This map shows where the classic panoramc routes are:
www.sbb.ch/content/dam /sbb/de/pdf/bahnhof-services/am-bahnhof/infra_services -uebersicht-karten-uebersicht-sts-panorama-de.pdf
The Wilhelm Tell Express is now called the Gotthard Panorama Express.
>> What suggestions for train line routes to take?
Others have given you good suggestions. I would just like to add that the standard route between Montreux and Genève/Geneva (already mentioned) is also very scenic. This route goes along the beautiful Lac Léman (Lake Geneva) and past the Lavaux vineyard terraces (a UNESCO World Heritage Site).
>> we will be visiting meringue on a day trip to lake brienze?
As you will be in Wengen for a full week, and plan to visit Meiringen, a scenic trip on the PostBus might interest you. As well as the trip from Grindelwald to Meiringen over the Grosse Scheidegg that I mentioned in response to one of your earlier posts, there is also a round trip (full day) from Meiringen over four passes of the central alps.
If you are interested, I have written trip report about it (with photos):
I have also attached a map of the route.
If you have time, I can highly recommend a visit to the Frutal Tea Room in Meiringen for meringues! It's open daily from 07:00 to 18:30 and is located at Bahnhofstrasse 18, not far from Meiringen station and PostBus terminus. I have attached a photo of a meringue dessert that I had there!