If you hike the trails it might not be very hard to climb the mountains out here. Off trail can be a very different story. a couple of trails that are 'easy' to begin with might be: Dungeness, Elwha, Hoh (first 13 miles), Bogachiel, East Fork Quinault. The intermediate might be: Marmot Pass, Tubal Cain, Mount Townsend, Mount Zion, Royal Basin, Dodger Point, Seven Lakes Basin. The tougher trails I can think of are: Lake Constance, High Divide to Hoh, and Goat Lake. There are quite a few trails that are not in the national park, so you can climb and shoot stuff too, Everything over 7,000 ft is in the park. Also last years snow didn't melt this year, so depending on this year's snow it might be tougher/easier(depending on what you like to walk on).