Does the 11 nights include the cruise? This is NOT recomended if it does. NO where near enough time required for touring interior. Look at add ons of at least 7 days. If you post what you are looking at, I will show you that all your time is in transit. As for the cruise choices- RCI has a big edge with going to Seward- but most people just pass through, if that will be the case with you- Princess is superior for Glacier Bay and College Fjords.
You may also want to really do your homework and research fully and make some good choices for interior Alaska travel. Most people do not, and as they find out what they have booked, are sorry. Most important is to budget TIME, most cruisetours do not. That is why you will see adjectives "hectic, fast pace, needing the cruise to relax etc" from passengers. Alaska shouldn't be traveled like that. If you continue with a cruise add on- be certain to have the Tundra Wilderness tour included- which most of Princess cruisetours do not. The Natural History tour is completely worthless. You will see that if you do some research. An option may be to go on your own, superior for doing what is your priority, especially if you are short on time, extremely simple to arrange. Good luck, the more you know the better.