One of our greatest hikes ever was when, during our 2014 epic road trip to Oregon and Washington, we did Hurricane Ridge [general info. available here] in Olympic National Park in Washington state. SO MANY MARMOTS, and many other cute animals as well. And, once the fog lifted a bit, the stunning landscape was revealed to us too. It was a pretty chilly hike (since you are, after all, on a ridge) but literally one of the best in my entire life. Click here for the entire photo album!
PS. The marmots are up on Hurricane Hill (see brochure for the breakdown of the different hikes), which is a 1.6 mile (each way) hike.