Hondo - according to Singlescruises the formal nights are 2nd nite and 2nd to last night of cruise.
Wow you are really going to take in the sights. I wish I had that much time off. Maybe next year when I plan better. This year will be to wet the appetite and help to make decisions on more land excursions.
I have a work acquaintence who is from Fairbanks and she is interested in making a trip and showing me the way next year. This is where I'll plan that week or more land travel.