Denali National Park and Preserve allows for backcountry camping. With that comes extreme risks as it is one of the most remote places that you can be. The National Park service does a wonderful job making sure that only a certain amount of people are allowed in each unit within the park. In this particular unit (north side of the Toklat river into the polychrome mountains) I saw the most wildlife I have ever seen while out backpacking. We found an animal spine, saw a moose, got turned around by 3 bears chilling in our potential camp location, and then at the end of the trip also saw 2 more grizzlies less than 30 feet away. Note; do not go here looking for bears, they are dangerous creatures and should not be harassed/seeked out in the wild.
If you do not trust your river crossing skills to the highest level, do NOT cross the rivers. My friend and I got stuck on the other side of the river with those aforementioned grizzly bears and had to camp an extra night in order to be able to cross the rivers as the water levels had risen. Backcountry adventures are inherently risky. Do not try them unless you are prepared. Bring bear spray, leave no trace, and ultimately experience the vast beauty that is Denali National Park.