I did this superb route on April 8 2022. It took 2 more hours than when I did the same thing 10 years previous, so I submitted the time/gpx from back then! I did that mostly with Mindy Knowles and Janet ? so am submitting it as Supported due to 'pacing' (we had no support). Photos from 2012 are on the Route page; photos on this FKT submission are from 2022.
The NPS has announced no plans to repair the Weeping Rock/Observation Point trail, so the full Trans Zion cannot be done, but this is an excellent route, with easier logistics (and no huge climb). I carried 1 lt of water and filled at 4 springs w/o purification. 4/8 was as early as it could practically be done this season, and the conditions were outstanding with only 100m total of snow on the trail. By May it becomes quite hot.