Sleep Issues/Ferry Issues

You might very well feel seasick even if there is smooth water. I do get seasick even on a big, stable ship. So bring dramamine. Also, dramamine can make you sleepy - so, it might be good to fall back on that if you need a push towards a relaxing night of sleep. If it's true that you have "severe sleep issues", then I would consider asking your doctor for a "relaxation" medication, such as Xanax; perhaps you don't really need a "sleep medication."

Secondly, I would believe that all Scandinavian hotels have blackout curtains.

I have not done this trip but looking at the route the boat takes I would expect it would be a smooth trip. Denmark acts as a breakwater a good part of the way, so unless there is a freakish storm, see no reason for heavy seas. If you were going in December, the weather could make the trip more 'interesting', but your time of year should be fine.

Also read some of the trip reviews and saw no mention by anyone of rough seas.

In as much as your posting is written in first person, singular, I presume you are a solo traveler. And, while there is a genuine benefit to the camaraderie of a tour, where fellow travelers socially interact, in my opinion, if there is anywhere in Europe when one does not "need to be on a tour" it is Scandinavia.
There is no destination or travel on the RS "Best of Scandinavia" tour that you could not easily do alone. In fact, you could easily improve it.
My suggestions are to watch the RS PBS shows on Scandinavia and take notes. You can see them right here on this site. What interests you? Then, I would make an itinerary of locations that have stimulated your interest. Do you want to go to northern Norway to see the Jotunheimen Mountains? Is it worth giving up a day in Oslo for that coach journey? Do you find the tantalizing island of Aero worth two days of your travel? Do you want to go to Kalmar for a day at the expense of an extra day in Stockholm or Copenhagen? These are not criticisms of the RS tour, but you are paying for them if you go.
You could fly to Copenhagen, spend as much time, there as you think it deserves, train to Stockholm, stay as long as you wish, fly to Bergen, hang out awhile (maybe take in the fabled "Norway in a Nutshell" tour), train to Oslo, explore my favorite Scandinavian city, and fly home from there.
A rail pass would be helpful and a money saver. I flew in July from Bergen to Stockholm for $55 - the reverse route was the same cost. I'd also suggest testing the waters with a friend who may also be interested in taking this adventure with you
Every hotel I've ever visited in Scandinavia has "black out" curtains. The Stockholm hotel I stayed in - directly across the street from the central train station - gave me an interior room and had no windows at all.
Public transportation in all four mentioned cities is a snap to use and driving in any of them is to be discouraged.
Scandinavia is expensive. Everyone will tell you that - because it is.
I hope this is helpful

We took a 12 day cruise out of Copenhagen and found it to be the most cost effective to see the region. Scandinavia is deadly expensive to travel on the ground and we assume the guided tour prices are also very high. We would hate to go that far and not visit St. Petersburg.
We took a Norwegian Air Shuttle from Copenhagen to Oslo. The flight was something like $100 and took an hour.
The Norway in a Nutshell tour was nice (but expensive), but the highlight was the Flam Railroad ride down into the fjord.

Hi,

I (solo) took the ferry once (ages ago) from Scandanvia to Germany, ie, the overnight car ferry leaving Malmö/Sweden to Travemünde. The time of the year was the second week in July, didn't have a cabin room, just sat with the luggage in the general seating area (Ruhesalon), got up and left the room too, just as the locals were doing. The ferry departed after 10pm, arrived at Travemünde ca 06:30. It was all fine, very satisfactory. Admittedly, I didn't get too much sleep but I wasn't trying to either.

I haven’t been on the RS tour but I lived in Sweden for a couple of years. I’m a light sleeper and the 3:30 am sunrises were an occasional challenge when the windows were open and the birds were singing.

1) Bring an eyemask. You cannot count on blackout curtains (although most places have them).

2) The ferries are big and the trip is generally smooth, but bring some dramamine just in case. It will make you drowsy which sounds like it might be a good thing.

I have used the ferry between Copenhagen and Oslo several times - latest this November. In my experience it is as smooth as a very gentle train.

We very much enjoyed the RS Scandinavian Tour (late June to early July). BTW - it was a terrific tour, #3 for us with RS (but many, many more independent trips to Europe). The hotels in Stockholm, Oslo & Bergen were quite modern and definitely had black out curtains; the Copenhaven hotel was a restored historic building in the center but the curtains escape me. The Aero Island B&B did not have black out curtains and same for the charming but rustic hotel north of Lillyhammer.

Our crossing to Oslo was rough due to high winds. I slept fine but my wife was not happy (she would not take Dramamine); our guide, Pal, remarked that the choppy crossing was unusual for this time of year and in fact was the only rough crossing he could remember.
The tour was great fun - go for it!

Everywhere has blackout curtains! It can be a bit disconcerting at first but you'll get used to it. I always just go to bed at my normal time, keep my "bedtime routine", and wear a sleep mask if any light creeps around the edges of the curtains.

Thank you all very much for taking the time to provide your suggestions. It is appreciated!!!!