Out of all the places I have visited in Alaska thus far, Lake Clark National Park is very high on the list.
It has been called the essence of Alaska and offers some of everything the state has to offer, along with being the junction of three mountain ranges: The Aleutian Range, The Alaskan Range, and the region's own Chigmit Mountains. On top of that, there are no permit issues, no crowds, and plenty of wild critters to see (yes, we saw a Mama Grizz with cubs and even a wolverine).
Picture this setting: you are standing on the pebbled beach of a turquoise glacial lake surrounded by snow capped canyon walls 6000' tall with only your pack and mind as the float plane that dropped you off fades from view. With no trails and only a topographic map as a guide, over the week you must make your way around the mountains on tundra, through heavy bush, and boreal forest in order to rendezvous with the float plane at a different lake.
We were only a few hours from Anchorage but it was the most isolated I have ever felt in my life. On the same trip we also visited Katmai NP and kayaked in Kenai Fjords NP.