We are going northbound July 19 on the Coral Princess with my 75 yr old mother. She is actually the experienced Alaska cruiser in our group. She loves it and so is sharing the experience with us! Northbound is what I chose because I want to see Alaska unfold gradually as we go. She has done the more sedate excursions such as Whale watching in Juneau, the White pass railroad in Skagway, etc. One thing I have learned is that she likes the excursions offered by the cruiseline more than booking independantly ,feeling she has more security in scheduling, etc. That's not the most economical way to go, but hey, I won't complain.
All the decisions depend on your budget. I am sure any cruise will be great for you. Just include her in the planning of your excursions. Have fun planning!