The weather in Alaska can be anything at anytime.
From friends have done cruise tours , do the land portion first
and then the cruise . The best cruise tours are Holland America
and Princess . The cruise gives you a rest after the land tour.
You could also do 10 day cruise from San Fran .
I can't remember (Princess ?) is going to have a 14 day cruise
from Seattle that actually docks in Anchorage not Seward
or Whittier.