I don't recommend them, HAL has 3 or 4 day cruises, getting on or off in Skagway, but the land portion first off is always more than 3-4 days, and still not long enough for the distances traveled. Way too much time on a bus.
CruiseWest has 7 day just excellent inside passage, going between Juneau and Ketchikan. Would be my top choice if money is no object.
You need the time, frankly, with 7 days the min. for an Alaska cruise.