My travel companions and I will purchase a 3-day Swiss Travel Pass Flex while we are in Canada. We will be leaving Chamonix-Mont-Blanc to travel to Zermatt. Given the Travel Pass only applies to the Swiss rail system, what is the best and cheapest way to complete this trip? I am thinking we need to purchase a separate fare from Chamonix-Mont-Blanc to the nearest Swiss rail station that is on a connection line to Zermatt (via Martigny perhaps). Any suggestions/recommendations are much appreciated.
Also, is it possible to reserve seats ahead of time when using the Travel Pass Flex? For example, travelling from Chamonix-Mont-Blanc to Zermatt it would be nice to know that we can make all our connections ahead of time. If yes, must we use the app or the website? Thank you very much for your help!