laundry

You'll find your answer here, under the heading, "while on tour":
https://www.ricksteves.com/travel-help/tours-faq

I always do laundry in the hotel sink when I go to Europe. However, that approach is certainly not for everyone! On the last Rick Steves tour I was on, some people took a few hours on a free afternoon to go to a laundromat. Others took advantage of the laundry service at hotels. There were some people that I suspected did not have to do laundry because they packed so much!

On our RS 17 Day Best of Italy, our hotels in Florence and the Cinque Terre offered laundry service.

I can get by in a 21" rolling bag without doing any laundry.
I get my jeans and khaki pants heavily starched, and they look good even after a week. And I take 6 to 7 golf shirts and rotate into a different shirt every day. It's no big deal to do 3 rotations of those shirts, as nobody ever notices.
I've also been known to toss away garments and buy some new clothes along the way.

I cannot speak for that particular tour, but the guide usually mentions towns that have a laundromat near the hotel. I have never used the laundromat. I have a "scrubba" . https://thescrubba.com It works well for me. I have been known to use the hotel sink too.

The trick with both methods I use, is a thin "travel/camping" towel to roll the clean wet clothes in and wring out to get tons of water out. The towel dries overnight hung over the shower door. I also use Rick's clothesline and another travel clothesline. I wash clothes in the room on the first night of a 2 night stay. I use the clotheslines overnight, where ever I can string them then when heading out for the day I sort of drape the clothesline in the closet; I try to hide the fact that my undies are still on the clothesline. I also use the supplied hair dryer to get some moisture out of things like socks, before they are hung up.

That works for me.

Layer, and you can wash undershirts and underwear in the sink on the first day of 2-day stays in a hotel. As for pants and "outer" shirts, I think one trip to the laundromat in the middle of your journey will work. I'd also be OK with paying the hotel for laundry service - I know it's pricey, but I hate laundry enough while I'm at home, let alone while on a trip.

I took the Switzerland tour earlier this year. Several of the hotels do offer laundry service, but they charge by item. Also most of the stops had a Laundromat near by. You could check to see if they had drop off and pick up service. I also washed my underwear, socks and some tops in the sink and they were dry by the next day.

I took Rick's Italy tour when it was 21 days and had the hotel midway through the tour do all my laundry. Clean PJs were wonderful!!! I sink washed at other times.

There will always be somewhere along the way to either have laundry done or do it yourself in a laundromat. Typically the guide/tour manager will let you know the best places at good intervals, or you can look in Rick's guidebook for laundry facilities. We've used a service (in Lauterbrunnen it was a fixed price for a load to be done in one day, not cheap but very easy) and found a laundromat (much cheaper and I could control how long my clothes dried to reduce the wrinkle factor).