This question haunted me throughout the trip for a practical reason. After coming back from an excursion at any given port, I routinely couldn’t find the places I had just been on any map of Alaska that I had handy, and kept going out to buy larger maps with the detail I needed. (My Internet access was unreliable; my iPhone screen size was highly unsuitable for the purpose anyway; and I wanted something I could both spread out in front of me and carry around.)
Before I left home, the maps I had from the cruiseline and the Lonely Planet guide were inadequate, so I picked up a guide by Fodor. The Fodor town maps (and photos) were an improvement, but didn’t help me find places outside the towns, so at my first Alaskan port (Ketchican), I stumbled across an independent bookstore and bought what I thought was a big fold-out map. Its type was so small that I couldn’t decypher the names on it without my reading glasses, so had to wait to get back to the ship (where they were stowed) before I used it. Back on the ship, spectacles in hand, I still couldn’t find Lake Harriet Hunt, where I had just gone canoeing that morning.
Finally, at the Saturday market in Anchorage, I bought a 156-page Alaska Atlas & Gazetteer (published by DeLorme) with topographic maps at a scale of 1:300,000 (where 1 inch represents 4.8 miles), and with persistent application, I was able to find the lakes, rivers and straits that I had visited via catamaran, raft, canoe, and kayak over the course of my trip.
But the map that gave me the best sense of HOW BIG Alaska is at a single glance is this one (and other ones like it):
As a Chicagoan, it helps me to see Alaska superimposed over the Midwest, running the length of Wisconsin and Illinois, not including the panhandle. The Alaskan cruise portion of my tour covers a distance comparable to that between Jacksonville, Florida and south central Missouri.)
If you’re from the American west or the east coast, this map might better help you get it into perspective.

That’s huge.
One of the best T-Shirts I’ve seen lately had an outline of Alaska with the Texas ‘Star’ in its middle, on the back of the shirt.
The front read “Texas, Alaska’s *****”
…brilliant.