I'm not a tour alum, but I have been to all the destinations you are considering.

I wouldn't presume to advise you on which option you should select. I agree with you on Ghent, Bruges, and Delft. I enjoyed them all, and they aren't the same, but they do have a lot in common. That doesn't mean I wouldn't advise you to visit them all. But in answer to your question, "Is this where we should spend our time?" I honestly couldn't tell you.

What I will say, though, is that if there are parts of Europe you haven't been and are interested in seeing, you could combine virtually any RS tour with a few days in Amsterdam on your own. And Amsterdam is a very easy city to enjoy independently: it's easy to get around by tram, it's flat and very walkable, and virtually everyone speaks English.

If the Munich, Salzburg, and Vienna tour is the most appealing to you, by all means do it. But take a look at some of the tours that will take you to places you haven't been yet and see if any of them get your heart racing!

I think Amsterdam is easy to do on your own. Since Dutch is not commonly spoken in other countries, everything is in English. I'm definitely not a fan of Brussels.

I think Amsterdam is easy to do on your own. I did it this past April in combination with Paris for 11 days. My co-worker is Dutch and gave me lots of tips and encouragement about trains in the Netherlands, super easy! We stayed in Haarlem a smaller and quieter city 20 minutes from Amsterdam. Delightful vibe. Also, I visited Delft and the Hague on my own via trains. I'm an art lover and enjoyed museums and almost felt like I never needed to step into another art museum in my life after the Rijks, the Hermitage, and the Van Gogh!! Also the Dutch Resistance Museum is a marvel of organization that tells the story of the Holland Resistance in WWII. Can't forget the Anne Frank House, the secret annex a sacred space and somber to actually be there after all I have read about it.
Another consideration is the Keukenhof gardens are at their peak late March to early part of May. We toured them and were treated to an explosion of glorious colors and scents. If you go in April, look into getting advance tickets.
I am signed up for the Munich Salzburg Vienna tour in Dec. 2019 for the Christmas markets festivities. I would imagine it is a wonderful tour to do in spring or summer and then go to Amsterdam either before or after.

Both are fine options. But from reading your explanations it sounds like Amsterdam is the main thing you want out of the first tour, the rest of it isn’t essential to you. Your other option (Munich etc) seems to be more appealing to you overall. If that’s right then definitely do option 2. Amsterdam is easy to do on your own. Rick’s book will have suggestions, and you can sign up for day tours as desired.

I would suggest considering combining the options and taking both tours on one trip to Europe. We've done that a couple of times because of the cost and hassle of flying to Europe and I'm glad we did. At the end of the first tour we had the excitement of taking the second tour. We also had a couple of days on our own between tours that was nice.

We were on the Heart of Belgium and Holland in April of last year and loved it. It has more art museums than some other tours and we really liked that. English was spoken everywhere and it felt very safe. There were fewer bus rides, the only bus days were between the towns when changing hotels, that was great. I liked all of the hotels but the first one (Hotel Harmony) in Ghent was our favorite. We went three days before the tour started and stayed at that hotel which was lovely (got a car service through the hotel to pick us up at the Brussels airport and take us to the hotel). We went into Brussels on our own for one day before the tour started, others stayed in Brussels before the tour but we like the smaller town of Ghent as our home base for those days.

Keukenhof gardens in April was wonderful. There are similarities between the charming towns on this tour but the tour is not that long and the towns each had their own charms to offer. These are really smaller towns (other than Amsterdam at the end) on this tour than the other that you are considering. We preferred being in smaller towns. If you take this tour I recommend taking the tram (on a free afternoon) to the Hague while staying in Delft to see the Rijksmuseum.

Your second tour option would have more music, bigger cities and the heat/crowds of the summer. You may prefer that trade off. I think Amsterdam is doable on your own, everyone speaks English, it's safe and friendly. Do watch out for bicycles while walking around there, they are everywhere and more numerous than I've ever seen. Hopefully you can arrange tickets in advance for the things you want to see there so that you don't have to wait in long lines to get into museums.

I'm sure you will enjoy and have fun and adventure on whichever tour you take. I've always thought that when I have a tough time deciding between two options that it's because both options are good - so in the end, I can't really make a mistake in choosing because either choice is a good choice.

If you want to visit the Keukenhof and see the tulips, the gardens are open only from March 21 to May 19th. I have been twice, once this past year in mid-April for a business trip and it was too early for the tulips and years ago the first week in May and the gardens were glorious. Here is the information. https://keukenhof.nl/en/. I would recommend that you target the trip in late April, early May for for the best garden views. Also, Amsterdam weather is chilly in the spring, but better in early May. You can navigate Amsterdam on your own. Transport is easy and efficient, they have Uber if you want a driver, and English is not a problem.

The rest of the tour options are really based on your tastes and interests.

Have a great trip,
Sandy

I agree with the other comments about Amsterdam being very doable on your own - use the guide book, it's easy to book museum tickets in advance (Anne Frank House, Van Gogh and Riksmuseum are easy to reserve well in advance and you will be glad you did), and it's easy to find your way around the city with a decent map. I would encourage you to stay in the city so that you get the full effect of the lights after dark - it's beautiful and I felt very safe there, and there are so many choices of restaurants, especially in the Jordan section. Haarlem is a very easy train ride and is worth a day trip if you run out of things to see and do. If you could fit it in, Bruges was amazing to see. It would make sense to take the Munich-Salzburg-Vienna tour -- there's so much to see and do in all those places. Small tip - in Vienna go to a baroque concert at St. Anne's Church (search online for it - it was a highlight of my trip - small gorgeous church with an amazing string quartet playing Bach and Mozart in the evening). Be aware that it can be very hot in those cities in July and August, but just pace yourself and take breaks to watch the people go by (while enjoying a refreshing glass of wine - after all, it is vacation!). Enjoy -- you can't go wrong with any of those places!!