Hi, Robie ...
What a wonderful cruise! Be prepared for chilly, though it might not happen. I'd take a cotton sweater and a rip-stop zippered jacket. We have jackets that fold into their own pockets and can be tossed in a tote bag. I'd also take a rain poncho. I was grateful for a lightweight sweat suit on deck almost every day in August.
We don't wear shorts in foreign cities unless they are clearly resorts.
It is a good idea to have some local currency for "walking around money". It is, in our experience, impossible to buy a Coke at McDonald's unless you have kroner, escudos, pfennings, or whatever. If you're touring on your own and using public transportation, you'll probably need local.
"Best buy" exchange rates are at American Express offices, but they're a pain to find sometimes.
One thing I don't know, and I wonder if you'd be willing to check it out? At the Hermitage, there is a charge to bring cameras in. Is that covered in the cost of your shore excursion or not? And do they take U$ for it? We just put the whole thing on a credit card. (Heck, there are a LOT of things I don't know, that one just popped into my brain.)
Not to sound like a broken record, but whatever you do, get your hands on the Lonely Planet Guide to Scandanavian and Baltic Europe. We self-toured the entire itinerary, including St. Petersburg and saw probably twice as much as the folks who were on ship's trips.
Shopping Hint: The Oslo Sweater Store has an outpost right at the pier, so it's a good place to take your first look. Best brand: Dale's. If you go to the downtown store and can't find what you want in your size, have them call the pier store. Prices are the same. Then put everything on one charge for the VAT refund. The trolley stop is very close to the pier in Oslo ... jump on and head for Viegland Park. We totally enjoyed getting back on the trolley and taking it to the last stop then turning around and coming back.
I have a gazillion notes on this itinerary, so if I can offer anything else, just ask.
pamda -- CruiseMates Utility Infielder