Travelling with Swiss Travel Pass in Switzerland?

Hi- I am travelling to Switzerland in May (13th -23rd) and plan to buy 15 day travel pass. Following is my itinerary:

• I Land in Zurich on 13th night and leave for Laussane on 14th Morning. I spend 14th and 15th with relatives.
• We will be travelling to Zermatt( to mattenhorf) for a night stay on 16th.
• And will depart for THUN on 17th. We will spend time around THUN doing waterways to Interlake / Brienz etc on 18th.
• Then 19th go to Broc through normal train from THUN and also visit Gruyere and back to THUN.
• On 20th leave THUN for Zurich.
• Go around Zurich and near cities like Lucern on 21st.
• May be do Titlus on 22nd. 23rd night depart from Switzerland.

My questions are as follows?

1. Does it make sense to purchase 15 days pass looking at the itinerary? As i am told that despite taking Swiss pass I will still need to pay for reservation in trains on most Journeys
2. Are trains full most of the time or is it easy to get a seat in Local trains
3. Basis my itinerary and the map shared by myswissalps.com for swiss pass validity i find from Zermat to Thun is a dotted connection so does this mean there will be extra charge on ticket despite having a swiss travel pass?
4. Are lake trips around Thun free on travel pass ? and is it easy to get a seat or do i need to book in advance ?

I ask this as some people say that swiss travel pass does not really reduces cost as for all trips you still have to pay for reservations each time.

Please help me clarify.

Welcome to MySwissAlps!

1. Either a Swiss Travel Pass or a Swiss Half Fare Card makes sense. Please see here for how to choose. Note that the Swiss Travel Pass is the most comprehensive pass for Switzerland. It includes trains, buses, boats and even some cable cars for free, and many museums as well. Passes that include seat reservations do not exist because reservations depend entirely on each individuals itinerary. Most people don't need reservations, and you don't need them either.
2. Mostly it is very easy to get a seat.
3. That's a tunnel and it's fully covered. It's explained here.
4. Yes, that's fully included and there's no need to book in advance. Just board with your Swiss Travel Pass. Please see the previous link for everything included in the pass.

Does this answer your questions?

Arno- Than you for your response. Let me go through the links you have shared and I will get back incase more query. thanks.