It's not a hiking trail. It's, in part, a "rebranding" of the existing Carretera Austral (a previously dirt highway built under the orders of Augusto Pinochet, now partially paved), combined with a tour ship cruise (between Tortel and Puerto Natales), and then a "rebranding" of Highway 9 down to Punta Arenas, and perhaps another cruise from there to Cabo de Hornos.
There is a Sendero de Chile (Chilean Trail) project, started by the government in 2000, which would have been a hiking trail that extends the full length of Chile. But that's a different plan, and has unfortunately been stalled...
The big Tompkins/Buckley bought-and-donated National Park, Corcovado, was established in 2005, and still has no access to the public available: there are no roads there, and no trails.
In the newer Tompkins park, Yendegaia, the Chilean government has begun to build a road through it. Access to the public is still limited.
His first park, Pumalín, was operated as a publicly-accessible private nature reserve from 1991, when Tompkins purchased the initial estate, until two years after his death, in 2017, when his widow finally turned over the reserve to the national park service.
The "Route of Parks" rebranding "es una propuesta de Tompkins Conservation" (is an initiative of the Tompkins Conservation foundation).
In my opinion, although it's wonderful what the end result of the Tompkins/Buckley efforts to conserve this land has been — let's not ignore the ugliness of how it happened. Wealthy American businessmen buying large swaths of the most spectacular parts of a South American country, using them as a private retreat during their lifetimes, and then turning them over posthumously, is not really a model to be idealized.
To flip the scenario: How would you feel if Jack Ma had bought Yosemite in 1991, set up the valley as a private retreat, lived down in the Ahwahnee until his death, and had his widow donate it to the federal government?
Edit:
For more context, two of the best-written, most balanced, English-language pieces on the Tompkins legacy and controversies are both from the Atlantic:
Eden: A Gated Community (1999) https://www.theatlantic.com/magazine/archive/1999/06/eden-a-...
The Entrepreneur Who Wants to Save Paradise (2014) https://www.theatlantic.com/business/archive/2014/09/the-ent...