Gobbler’s Knob is a fire lookout (5,500 feet) that can be reached from Round Pass on Westside Road near the Nisqually entrance to Mount Rainier National Park [1].
This 2.5-mile trail passes Lake George. Westside Road is closed at Fish Creek, three miles up, due to recurring floods that have washed out the road, so you may need to wade across (sometimes this is not safe). The area is always prone to floods and mudflows.
Bikes are allowed on the road (but not off the road) beyond here, but be sure to get current conditions from the Park Service before heading up.
The lookout is also accessible from outside the park via the tiny Glacier View Wilderness [2].
Links:
[1] http://www.moon.com/destinations/washington/south-cascades/mount-rainier-national-park
[2] http://www.moon.com/destinations/washington/south-cascades/mount-rainier-national-park/mount-rainier-wilderness-ar/glacier-view-wi