Welcome to the Forum Brian and thanks for your posting. I believe we met up last month both near FC Saddle and later again in the SFTH lot and if I have that right–many of us online would certainly enjoy learning more about your father’s Ranger legacy and family’s collective SGW history going forward!
I’ve not explored the drainage down below Big Tree nor the general North Meadows zone post-Lake Fire–and figure if anyone had it would likely be SGWA Ranger John H. (come in, over), Chris from Redlands or Hikinjim.
[Suggest also checking out the SGWA FB page to connect to other wilderness users who seemingly don’t partipate here…]
Current Googie-E images indicate a prolonged descent of deadfall-laden bushwack down the drainage, followed by this snaky descent into the wash–there may lie some dragons (?):
BLM currently has a fire closure zone due north of Whitewater Preserve (presumed exit point?) which can be bypassed by intercepting and taking the exempted southbound PCT . Car to car logistics loom pretty large here…hope you have cooperative significant others!