Alaska has far more country than it has roads, and a campervan can only follow the roads. Out of Anchorage the road system splits two ways, and picking one is most of the planning: south on the Seward Highway to the Kenai Peninsula and the fjords at Seward, or north on the Parks Highway to Denali and the Interior. A few days is a Kenai trip. Ten days can hold both, and Fairbanks sits at the far end of the northern one.
The night is the scarce half of an Alaska van trip, and which system you are booking depends on which way you turned. Seward runs municipal loops on the waterfront, Denali's campgrounds go through the park concessioner, and the pads up Chena Hot Springs Road are first-come. The Anchorage lander covers getting the van. This page is about which way to point it.
The Kenai Peninsula and Kenai Fjords
For a rental of a few days, the Kenai is the whole trip. Seward sits about 126 miles south of Anchorage, the first stretch of the drive running along Turnagain Arm, and Kenai Fjords is a park you see from a boat out of the harbor there rather than from the road. Exit Glacier is the one piece of it you can drive to.
Seward's waterfront campgrounds, the first night south of the city, and the longer run west to Homer are all on the Anchorage lander.
Denali and the Interior
Add days and the second leg runs north. The Parks Highway climbs 240 miles from Anchorage to Denali's only road entrance, spruce taiga opening into tundra with the Alaska Range along the skyline. The park road, the buses that run it, and the campgrounds along it are a planning job of their own, and the Denali lander carries it.
Denali caps vehicle length at its campgrounds, which matters if you are weighing a van against something bigger. The RV rentals for Alaska cover the larger classes.
Fairbanks and Chena Hot Springs
Fairbanks is the add-on, and it earns its days only if the rental is long enough to spare them. The Parks Highway keeps north past Denali into town, and the day out of Fairbanks is Chena Hot Springs Road running east into the state recreation area, ending at an outdoor hot pool. The overnights along that road, and the haul road north toward the Arctic Circle, are on the Fairbanks lander.