Princess does a great Alaska cruise itineary.
Look into the Sun Class size ships.
I would strongly suggest you let a travel agent handle this for you. Its always so much easier to let a TA handle a group. She might be able to get you some discounts or perks that you cannot get on your own. Not to mention the peace of mind for you not having to handle all the little details, questions, or potential problems that could crop up. If anyone has any questions all you would have to do is to tell them to call the agency and ask to speak to the specific agent who is handeling the booking for you.