Hello,
This would be my first time in Switzerland (well, I've been to Lugano, but it's right at the Italian border and it was for a very short afternoon visit, so I don't really count that, ha ha). My party of 3 (senior and 2 adults) will be based in Lauterbrunnen for a few days in late May - we plan to do some hikes in the area with visits to Mürren, Gimmelwald, and Wengen along the way. I didn't purchase a Swiss Travel Pass for us. We will be coming from Rome. I purchased train tickets for my party of 3 on the SBB website, departing from Rome and arriving in Lauterbrunnen. We were designated seats from Rome to Milan and Milan to Spiez but not from Spiez to Lauterbrunnen. I'm assuming that we're free to pick our seats upon boarding? Or do I need to go back to my booking and reserve seats for that leg of the trip? Also, since we're crossing into a new country, where would we get our passports stamped in Switzerland? We are USA citizens. We've never taken a train crossing an international border, so we're not sure how customs/port of entry procedures work.