On embarkation (arrival) day you're required to be on board the ship 2 hours pre-departure. You'll be expected to attend a short muster drill before the ship departs. There is no standardized time, but often for cruises in which the ship spends a night at the embarkation port, it is around that 2 hour mark. Almost always, from what I've heard, it does NOT affect dinner.
As of Sept. 2015, the "back on board" time was a half hour pre-departure time for the remaining ports. Viking will tell you every day what that time is. If you're tendering (getting on a small boat to be taken ashore) the time of the last tender will be announced as well. For us in the Med in 2015, it was a half hour pre-departure.
You have to take your ship key card with you when you go off the ship, as well as when you leave the room, of course. (The doors won't stay open even if you want them too - fire suppression technique, I suppose). The card will be scanned when you leave the ship and scanned when you return. You may also have to show it to get into a port area or port terminal. I carry a lanyard-type thing to hold mine (photo here): http://www.pbase.com/roothy123/image/165572124
You'll need to put bags through an x-ray when you return to the ship - or sometimes in a port terminal. (They are not looking for alcohol, just dangerous things.) You'll also go through a scanner.
It's a big ship, so when I get on board, I usually make note of what's around each elevator bank, and whether I need to turn right or left to get to my room. (They're are two banks of elevators, although I'm thinking one may be smaller than the other.)
If anyone mentions "port side" it's the side on the left as you're facing the water ahead. Please call the ship a ship, not a boat. These ships are 48,000 tons of ship!
Ocean cruises often stop in places where the dock is far from center city. Keep that in mind when making plans. Of course, in just about every place I've been, especially Europe, cabs were lined up waiting for fares, so you're not stuck. Also note that just because a cruise ship docked a particular place last year or last week, that doesn't mean it will dock there on your cruise. Dock (or tender) locations and decisions are dictated by the port, not the cruise line. (Sorry, no walking through other river ships to get to yours!)
Occasionally (in some ports) Viking (and other cruise lines) will keep your passport for most or all of the cruise. In many ports, you'll be told to that an ID ashore. These things are usually dictated by the countries you're visiting. Some countries require that no food be taken ashore. Remember to take the quiet vox box on tours, although occasionally the tour guides won't use them. Remember to charge them after use!
Don't forget there's an electrical outlet alongside the bed. There's also a coffee maker (very strong coffee in my opinion), hairdryer, and snacks and binoculars in/on the desk. (I love that desk!) Your room steward can get you more hangers if you want. If the coverlet's too hot at night you can ask for something else. We put our luggage under the bed. We usually take a few basic meds like Tylenol and Pepto Bismal tabs. However, there IS a doctor and nurse on Viking, and I think there ARE basic things like cold medicine in the ship store. However, the store isn't always open (mostly closed while in port due to country regulations). If you need something, I think you can call the nurse 24/7, though - ask at Explorer's Desk. You can view Viking info (restaurant reservations etc.) on the TV.
Mid-cruise Viking will send around a questionnaire asking or verifying how/when you'll be leaving the ship. Then they'll assign you a time to depart. If you have independent plans, it sounds like you can leave fairly late, at least compared to what other cruise lines do. You'll have to be out of your room by around 8, though. Viking puts all bags ashore, after you place them outside your door the night before. (Therefore you need a small carryon, or at least a bag! Keep out what you'll need in the AM. Viking will have this and more spelled out in their disembarkation information.)
If you have a Viking transfer to the airport, expect to get up VERY early. It's just what cruise lines have to do....
If you want to be outside on the deck while the ship's moving, or after dinner, you may need some warm clothing. It's always colder in the wind.
If you want a quiet but possibly salty place to be by yourself with a 360 degree view, the aft part of deck 2 is a winner. I'll probably be there for cruising the last half hour to Geiranger and other places where I want to do photography without a crowd. It was an excellent spot for our departure from Kotor in 2015.
If you tender, wear decent shoes and try to keep both hands/arms free. The tender crew like to be able to offer a hand with tendering, as steps and low ceilings can be a bit tricky. I'm pretty mobile and coordinated, but still, I usually put my arm out so they can grab it and help me.
Don't miss eating dinner at least once in the World Cafe. It's not an ordinary buffet - and if the weather's good, you can eat outside. Also, if you like scones, hot ones, plan to eat dinner late that evening - very filling and great.
If you're looking for a library, there isn't one. However, there are books scattered about in various places. Go looking...
Someone else can probably fill you in on the latest tips for getting additional specialty restaurant reservations, if that interests you. I'm running out of steam...
I have some photos and documents from our 2015 cruise that might be helpful to look at. Just keep in mind things may have changed since then. Here's link: http://www.pbase.com/roothy123/viking_star_&page=all
Enjoy your cruise. I know you will.