My husband and I are cruising the Rhine to Amsterdam. We start in Basel. Any advise on what we'll see? What to try ( food ) that we'll never get in USA?
Hard to answer since we don't know your itinerary. Most tours go to Strasburg, Heidelberg, etc which are wonderful. The section of the river known as the Upper Middle Rhine is a stretch with loads of castles and the Lorelei. Takes about an hour to cruise through. The rest of the Rhine isn't that scenic.
Basel is a nice city with a lovely cathedral, red Rathaus, and the Tinguely Fountain (a garden with kinetic sculptures). In other ways it's a business city.
If you list the stops on your tour you'll get some more suggestions.
You need to give the month of travel, especially since you are interested in food. It's not as true as it used to be that certain international foods are unavailable in the USA, but there are some preparations that are unique and regional. On river cruises, there is a substantial group of passengers who don't want to give up prepaid meals on board, so excursions tend to return you to the ship for lunch. You may wish to set aside money and time to eat locally. This requires planning if the ship's port is not walkable to local restaurant areas.
Are you flying to Basel, or to Zurich, with the cruise company bus to Basel? Does your question apply specifically to Basel, or to the entire trip, whose stops you have not listed? Some cruises nod towards the departure city with an event there. What are your travel plans after disembarkation from the ship?
We did the Viking cruise, Amsterdam > Basel a few years ago. As mentioned, the included and optional excursions are usually timed to get back to the boat for lunch / dinner. So if you give up the included excursions, and the included meals to eat out on the local economy, you'd be giving up the two biggest features that you are paying (a lot) for anyway. And there's not a lot of time in port to spend. Especially if the boat is docked away from the center of town and you need taxis to get there and back.
There were a couple of organized dinners in town as optional afternoon excursions. There were some local dishes served on the boat as a nod to where we were, but overwhelmingly American. We'd often buy pastries or baked goods and cheese, in town (quickly, not to lose the group) to bring back, but only once did we have time for a lunch on our own. That was on the square in Cologne, where there was more time (boat docked within walking distance). And that was where we first tried Kölsch, the local beer which is recommended you try if you like beer. Not the same in the US.
Most of the actual cruising is at night. The most scenic part, the Middle Rhine, is during the day, so you see what you see in the commercials. The rest of the Rhine is not that scenic. So you pretty much have to get off the boat in ports, to see anything.
One of the included excursions in the Netherlands included a stop at a cheese making operation (including the cows) where we had the opportunity to buy several varieties of Gouda cheese. That was interesting to taste and compare to what we buy at home. I bought several pounds home.
Bottom line is that there wasn't much time to sample local foods, without giving up much of what the cruise offers. It was worth it for us, and we'd do it again. Its just not the cultural immersion experience of a tour, and most of the passengers were OK with that.