The Glacier Gorge Traverse and Rossiter's "Walk in the Park" are two related routes in Rocky Mountain National Park. They cover some of the same terrain, but they are different. The naming is confusing since the "Walk in the Park" traverses Glacier Gorge proper, while the Glacier Gorge Traverse encompasses Glacier Gorge, Loch Vale, Chaos Canyon and Tyndall Gorge. Both routes start and end at the Glacier Gorge TH in Rocky Mountain National Park. The Glacier Gorge Traverse has it's own route page here.
"Walk in the Park": According to Rossiter's description on mountainproject.com, this route summits Thatchtop, Powell, McHenry's, Chief's Head, Pagoda, Longs, Storm and Half Mtn (described counter-clockwise). In addition, Rossiter says you should take the Keyhole Ridge route between Longs and Storm, which is quite a bit harder than some of the alternatives (such as the standard Keyhole Route). This route was first completed by Richard Rossiter in 2009, and he posted it to mountainproject.com later that year. Here's the route on Strava: https://www.strava.com/activities/391717326
Glacier Gorge Traverse: This is a longer route, but the eastern part is the same. Going counter-clockwise from the Glacier Gorge TH the route goes up the trail to Bear Lake and then to Flattop Mtn. From there you summit Hallett, Otis and Taylor before joining the "Walk in the Park" route on Powell and continuing to McHenry's Chief's Head, Pagoda, Longs, Storm and Half. The Keyhole Ridge is not required (you can use any route on Longs). Before Powell the peaks are all easy, non-technical climbs. It's about 19 miles vs. 15 or so for the "Walk in the Park". A variantion of this route, going clockwise and summiting Mount Lady Washington instead of Half Mtn, was first completed by Jim Disney in 1982. It was Disney's 6th attempt at the route (the first being in 1966!), and he said that "I’m told others have also tried and failed."
Note: We have flagged some earlier completions which skipped Keyhole Ridge and used an easier route (either the North Face or the Keyhole Route). Rossiter's description clearly includes Keyhole Ridge, which is a major route, so bypassing that part of the overall route is not acceptable for the FKT.