I hope it is doable because in late may I'm trying to do the valley floor to Cloud's Rest and back in a day. Yeah it will likely destroy my body, but it seems to be a challenging hike. I did Cloud's Rest from Tuolumne Meadows in 2010 and people were dayhiking from the valley at getting up there by noon. Not sure if they continued to Tuolumne or went back to the valley though. Anyway's, let us know how your hike went.