I'm taking my parents (both 65+) on their first cruise for their 45th wedding anniversary. We're considering the Carnival Spirit, Alaska Inside Passage the end of September in a category 11 suite. I've read so much about all the cruise lines that now I'm just confused. Any advice about whether this would be a good choice for a fairly quiet, older couple? They are very informal, but it looks like the "formal evenings" are not as important as they used to be on cruises. Help! This would be a very expensive mistake if I'm on the wrong track! Thanks!