The route we took in Yosemite was Rafferty Creek to Merced Lake to Sunrise Lake to Cloud's Rest to Tenaya Lake. I believe it was around 42 miles total. There are many variations of that route, that's the one we chose because that was the permit we could get. The elevation change will be the toughest thing for you, so just plan accordingly.
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https://alltheadventures.com/2016/08/01/zion-the-subway-top-down-route/