I'm with Paul. First Alaskan cruise go to Glacier Bay. We loved it even more than when we visited Hubbard Glacier (which ain't bad, believe me).
This would eliminate some cruise lines too. One of our Alaskan trips was on HAL Zaandam. You can't go wrong. Beautiful ship and line. We also sailed NCL and had no problems at all and we sailed Celebrity (but no Glacier bay).