I just recently returned from the June 26th sailing of the Norwegian Star. Let me just say it was a fabulous trip.
First of all, we arrived in Juneau at 12:00 pm and yes, you will tender until the Norwegian Spirit departs at 2:00 pm. The NCL Star then repositions to AJ Dock at 2:30 pm. You'll want to get your tender tickets early so you can be among the first off.
AJ Dock is not within walking distance of downtown Juneau, but NCL (among other cruise lines like Holland America and Princess who use the dock as well on other days) has non-stop bus service from the Mt. Roberts Tramway in downtown Juneau to AJ Dock and the Norwegian Star. The bus ride is a whopping 2 minutes, 45 seconds. Yes, I timed it. The wait for any bus is less than 5 minutes. It is not at all inconvenient.
Note, if you get off the tender and have a late shore excursions, you will need to go back to the ship to catch your excursion. Again, not a big deal.
Recommendation, if you have time, take the Mt. Roberts Tramway to the top of Juneau. Approximately $23.00 / adult and $14/kids. Great view of Juneau and you can get watch the Star move into position. Super hiking trails too.
Finally, whatever you do, DO NOT MISS THE BUCHART GARDENS WITH FIREWORKS TOUR IN VICTORIA. From 10:15 pm to 10:45 pm, you will see the most amazing display of fireworks in your life. DO NOT MISS IT. Every Saturday night. The last one is September 4th. DO NOT MISS IT. It's the perfect way to cap off the cruise.
Here is a picture of the NCL Star in Juneau Bay from the Top of Mt. Roberts.
Enjoy your cruise. We had a blast.