Suzan, Princess has traditional early and late seating, but also has "personal choice" dining, which is similar to Norwegian's Freestyle dining. Most cruise lines have alternative dining choices at dinner, so that even if you sail a cruise line with just early or late seating for dinner, you have the option of going to the buffet restaurant or one of the other alternative eating areas at whatever time you choose, within the hours of service of that restaurant.
Most of the more expensive cruise lines have "open seating," which means you show up at the dining room whenever you want and they seat you at that time (within the hours that the dining room is open). Cruise lines have limited tables that hold just 2 people, but they can usually accommodate a party of 2.
I know that the Sapphire Princess, among other Princess ships, stops in both Ketchikan and Juneau (and Skagway) on both northbound and southbound itineraries, as do most other cruise lines' ships that do 7 day cruises. The southbound itineraries, where you do an inland tour first and then cruise for 7 days from the Anchorage area (Whittier or Seward)sell out faster than the northbound itineraries that start in Vancouver, end in Whittier or Seward and then you do your inland touring. That's true of all cruise lines that do Alaska. If you want a 7 day cruise and no inland tour, you can also do a cruise that starts and ends in Vancouver or Seattle.
Alaska cruising enjoys a short season of just a few months each year, and space sells out quickly. If you want to sail in July, I'd contact a knowledgable travel agent soon to see what kind of availability there is.