Walmart has the cheapest prices on the basics?? All your souvenier stuff from books, candy, postcards, tshirts, trinkets etc etc etc. Alaska Jack are chocolate candy bars, about $1.50/bar very nice artwork on the wrapper. Be VERY selective on the ULU, there are many made in China products. The Alaska State Museum is right downtown, the cemetery is farther away, past the Govenor's house. Head to your library or bookstore. and pick up Frommer's Alaska, Fodor's Alaska, a good downtown map and walking tour guide is enclosed.
You need to get going now with your plans if you are leaving this weekend ( I am too).
As I have mentioned, you are adding at least an hour of shuttle time, if you do not combo book your helicopter and whale watch. If you don't care about the extra time, perhaps use it to get lunch on the ship, then head back out. BUT you may at this time, have to book a ship whale tour, which I would look to do so now. Do you have accomadations for Friday night??? I'll assume you already have your car lined up for a downtown Vancouver return (NOT airport)? Again, you need them. Myself, I stay in Bellingham, 2 hours north of Seattle then an hour+++ to Vancouver. Offers far less wait in border lines if you get going in the morning by 10am and a little sightseeing of Vancouver. Be sure to have a downtown Vancouver map. ALL city driving to port.