We chose this cruise because of the port itinerary. Our focus is the ports of call, verses the ship itself. But both are highly recommended here.
We made our own travel arrangements, including booking the cruise online. For the first night we stayed at the Crown Plaza Copenhagen Towers, but I would recommend at least two nights in Copenhagen pre-cruise. This modern high-rise hotel is highly recommended and a common pre-cruise hotel. The advantage during summer is A/C and a quiet room. The nearby mall closes at 8pm. The front desk sells Metro tickets. Just about everyone we ran into in Scandinavia spoke English, most without an accent.
We were extremely lucky with the weather for our cruise from August 8th to August 19th. No rain on excursion days and most days were sunny. Several days were warm enough to swim in the ship's pools. We were prepared for rain, but not for the wind during rain downpours: typical umbrellas reverse in the wind.
We were extremely lucky the Emerald Princess has a very knowledgeable and independent port lecturer: John Lawrence. He was very funny in person during his talks. Had I to do it over, I would have purchased and watched his DVD titled "Baltic Treasures" in advance.
Also the book "Northern Europe by Cruise Ship" by Anne Vipond was useful along with the http://istopoli.com/cruise site. Princes Cruises has a downloadable PDF that describes the excursions which was very helpful and be sure to make your shore excursion reservations online before the cruise.
You only have about 9 hours at each stop, so you have to spend your time wisely. The exceptions are Stockholm at 7 hours, so we will have to return on own someday, and at St. Petersburg which has a lot to see.
The disadvantage of HOHO buses is sometimes you have to wait 30 minutes for the bus to pick you up. The advantage is price. Using cabs at key points will save you some sightseeing time.
Small amounts of local currency via local ATM's for WC's and trinkets are a good idea. Some places require photo permits. City Halls are good attractions in Scandinavia.
Oslo, Norway: Much is walkable; ship docks at city. National Gallery allows pictures except for one room. Need bus to get to worthwhile Vigeland Sculpture Park and need krone for the WC next to it; no ATM at park. (Norwegian Krone)
Aarhus, Denmark: Most boring. We took ship's tour to see the countryside. Not sure what the best choice is here. Have some local currency via local ATM. (Danish Krone)
Warnemunde, Germany: Instead of 6 hours traveling to/from Berlin, we took the ship's tour to Schwerin Castle, Lake Schwerin Cruise, lunch, & St Mary's Church. Well worthwhile. Castle allows pictures. We were lucky to visit Warnemunde during the sailing festival, highly recommended to watch during the sail out with horns blaring. (Euros)
Tallin, Estonia: Walkable, no bus/tour needed. For WC need Euros and only good one is at entrance to Old Town. Take taxi to TV tower early in morning, if interested, otherwise long waits. Town Hall tower is very difficult to walk up. (Euros)
Saint Petersburg, Russia: Took the most popular two day bus tour from Princess. My guess is a private tour would be better. With respect to the Peterhof Palace: long travel time, extremely crowded, long waits for WC, no pictures. Recommend seeing outside only. Outside WC there requires rubles (no line). Actually the Peterhof Palace was mostly destroyed in WW II, so what you are looking at inside is a new reconstruction. Other places have far better interiors. Hermitage museum allows pictures, and has great interiors, so maximize your time there. Be on deck as the ship leaves through a new narrow levy. (Rubles)
Helsinki, Finland: HOHO bus a good choice here. (Euros)
Stockholm, Sweden: Took John Lawrence's advice and did HOHO by boat and saw Vasa Museum first thing. Royal Palace Apartments were very worthwhile, but no pictures. Take cab to city hall for tour. Be on deck during the three hour entry or exit to Stockholm. We did not do Skyview, which requires reservations, so best to do on tour. (Krona)
This was our first time with Princess. I was skeptical of the tipping system but it worked out fine. The staff was very friendly and helpful. Lounge music was varied and very good.
Formal dining room service was excellent. What to drink at dinner was a problem, since only iced tea was free, in the formal dining rooms. This was the first cruise I signed up for free beverages and I am glad I did with all the free juices and sodas I could drink. Free afternoon tea was served in a formal dining room.
The passengers were mostly older on this cruise. There were few children. Nevertheless, doing this port intensive cruise when you are younger is even better: lots of opportunities to do a lot of walking.
There were plenty of taxi's on the way out. A flight leaving Copenhagen at noon seems about right except on Sundays, when 11am would have been good enough. You have to be out of your cabin at 8am.
Having two point & shoot dedicated cameras are better than one, in case one fails (battery or lens lock), at a location you will never have a chance to return to. And since they have different specs, you pick the right one for the picture.