Though most of the climbing in the park is committing, hard alpine, and much of the rock outside of the Ruth Gorge (and much in it, too) is $#!&e, there are fun diversions to be had for climbers in Denali National Park in the form of glacial erratics. These boulders, often mind-bogglingly enormous and of rock types not found for dozens or more miles around, are scattered randomly about the park and can be fun day-hike destinations. They're usually good rock, too, as the crumbly stuff doesn't survive the rough journey of a glacial conveyor belt.
Oh, yeah -- don't bother bringing your crash pad along. Getting anywhere in the park requires cross-country thrashing through willows and alders. Trying to drag a pad would double or triple your approach time, if it were possible at all, and thrash your pad to boot.