Best Time

With the exception of Denali Natl Park, we saw most of our wildlife driving on the Alaska Highway. We saw black bears and bison in BC and grizzlies in the Yukon. We saw moose everywhere though. We only saw one black bear in the wild while in Alaska. We saw lots of sea life on a glacier tour (Stan Stephens Tour) from Valdez.

We went the last week of May. Still cool and wet weather but we just took rain jackets with zip in liners. Saw bear cub in the road and moose in Denali park. Ditto on Lulu-Belle in Valdez. All day cruise, stops for lunch at glaciers for viewing. Well worth the cost!! Lots of sealife and narrated tour.

Ditto on Alaskan Highway in early spring for animals. We saw more wildlife on the highway than we did during our two summers of 4 months each.
While on your loop spend a week at Teklanika in Denali and ride the first shuttle bus each morning. You will see a lot of wildlife!
Take a sightseeing cruise out of Seward for sea life.
Go for a cruise on the Lulu-belle out of Valdez for whales and glacier vews.
That should take three weeks and whet your appetite to come back and spend the summer when you are able.

We took the train from Whittier to Denali National Park and did not see even one critter from the train. If you want to see animals drive the Alaska Highway. We have driven it twice. Beautiful scenery and plenty of wild animals on and next to the highway.

Early spring, such as late April and May, for wildlife, but it is a bit of a guessing game. In summer I mostly see moose in the urban areas. In late May I have seen a moose running thru the back lot area and a minute or so later a grizzly on a scent chase.

Pick a time based on your schedule and just have at it.

The animals we saw were wild and in their element. We did not see large numbers of animals which is common. If the weather is clear you'll see scenery, might be January or July as no one knows. Yellowstone would likely be better...

June and July for the most daylight and warmer temps.