There is a parking area on the loop near the trailhead north of the Lodge at St. Edward State Park. Here’s a link to the park map. There will be volunteers and signs to point you in the right direction.
Your tow vehicle must have a Discover Pass. If you do not have a Discover Pass, you can purchase an $11.50 Day Pass or a $35.00 annual Discover Pass from Washington State Parks staff. Visit the Discover Pass website for more information.