Well, my tour was in 2014 so some hotels have changed hands, some have probably changed altogether. They were all fine.
My tour stayed in Stechelberg in Switzerland and this is one of the hotels that has the possibility of shared baths. I was in the annex across the lane and had a shared bath situation with other RS tour members. There were 2 solo travelers and 3 couples sharing a toilet, men's shower and women's shower. The showers and toilet were all in separate lockable cubicles. Each room had a sink. This is not my favorite hotel situation but to be honest Switzerland is so fantastic I managed. I think there are some tours that stay in Muerren now but just a head's up. The Hotel was Hotel Stechelberg. Here is the website which looks weird but gets you to the right place.
https://hotel-stechelberg.hotelescuatroestrellas.website/
There were a couple of people in my group who felt a little nauseated when we went up to the top of the Schilthorn but were fine as soon as they descended. Most of the group went on the Mannlichen to Kleine Scheidegg hike (facilitated by the guide) and I do not believe anyone was ill on that. We mostly all took it pretty slow as the scenery was so outstanding you couldn't possibly NOT look, hahaha!!
I do recommend you do some walking/training for this trip. I was walking a LOT before this one and it was so helpful. The days in Amsterdam and Rome were near to 12 miles total for the day (not 12 miles straight - breaks, lunch, etc). What I did not do and wished I had was to add stairs or hills into my walking routine. Rome is hilly! LOTS of stairs! I'd want to at least be able to walk 4-5 miles. You don't have to but you'll have more fun if you don't feel like your feet are going to fall off.
Shoes - Make sure you can walk the aforementioned 5+ miles in your shoes. Make sure they are broken in and comfortable. Do not take shoes that are new or that give you a blister at home, no matter how cute they are, lolol.
For Venice - be ready to just take a small day pack with a packing cube with spare clothes, toiletries, chargers minimal stuff. You can leave your regular suitcase in the bus cargo area. The bridges in Venice are steps and it's easier to manage if you just have something light with you.
Pack light - You probably know this from your other tours but try to get down to a 22" or smaller bag. NO ONE on the tour is going to notice what you are wearing.
Although it's old, here is a link to my Trip Report.
https://community.ricksteves.com/travel-forum/tours/21-day-best-of-europe-8-26-14
I've now done 11 Rick Steves tours as well as 12 Road Scholar tours. This remains one of my favorites. I loved the itinerary, I loved the guide (Dimitri!!), I loved my group, EVERYTHING! I know at least one regular forum member has taken it twice! That is tempting!
