Yes, much of Alaska is still wild and inaccessible by vehicles. But the same is true of the Yukon and the Northwest Territories of Canada.
Yet, just to drive whatever roads there are would take a lot of time, particularly with all the pot holes, frost heaves, and gravel and muddy patches. It would take more than one summer.
People who take an Alaskan cruise do not really experience Alaska. And even people who go on an extended land tour only see the corridor from Whittier to Denali, or perhaps up to Fairbanks, along very well traveled paved highways.
Be sure to spend a lot of time at the Morris Thompson Visitor Center in downtown Fairbanks. They show excellent documentary films about Alaskan places that only the really avid adventurers get to see in person. I am glad just to be able to see it on film. Yes, we spent several days in Fairbanks, visited the center every day and got to see all their films. And we were there during the Midnight Sun Run, and the downtown festival. We enjoy Anchorage too, but stayed for longer in Fairbanks.
And when stopping at Mile 0 in Dawson Creek and visiting the Visitor Center, be sure to allow enough time to watch the video on the building of the Alaska Highway that is shown in the back room. It's about 1-hour long, and we really enjoyed it. There was some footage that we did not see in documentaries shown in other places.
PS. We saw a lot more wild life in the Yukon than in Alaska.