Key here is to educate yourself and do your homework on what is available. TA's rarely have even been to Alaska and sell sometimes based on commissions or sales brochures.
Look at - ports, time in ports, glacier, route, ship naturalist, price- then find your ship.
I do think HAL has one of the best round trip Vancouver itineraries around that include both Glacier Bay and Tracy Arm. As for one way, same line if it includes Glacier Bay and College Fjords. Princess is a close second. NCL has the Star which has Glacier bay, but sails round trip Seattle, more outside passage sailing. ANY cruise will involve compromises and Alaska is never a one time trip.
So determine what route you are looking at- round trip or one way- my opinion only, I never do one way trips without at least another week to tour the interior. Take advantage of being there.
Head to your library and take out Alaska travel books, Frommer's Alaska and Fodor's Alaska are especially concise. The more you know the better. I aways book my own air, simple, if going one way look at the multi city option and not two one way tickets.