catware, I fly at levels similar to, and lower, then what you show in your video quite often in a helicopter. Depending on the mission as well as the current conditions it is not uncommon to fly at such levels. There is definitely a chance for you to come across a manned aircraft there and at those altitudes, unless there is some charted reason on sectionals where that airspace would be off-limits of course, in which case no one should be flying in it without prior approval (i.e. prohibited, restricted, TFRs and other restricted areas).
Also, just a heads up, that area of airspace, near huntington lake in CA, has many marked national park boundary areas, mostly to the north and to the east, just to warn you. Part of that reg would make it so that you should not fly in that area: "b. Pilots are requested to maintain a minimum altitude of 2,000 feet above the surface of the following: National Parks, Monuments, Seashores, Lakeshores, Recreation Areas and Scenic Riverways administered by the National Park Service, National Wildlife Refuges, Big Game Refuges, Game Ranges and Wildlife Ranges administered by the U.S. Fish and Wildlife Service, and Wilderness and Primitive areas administered by the U.S. Forest Service."
FAA Advisory Circular AC 91-36, Visual Flight Rules (VFR) Flight Near Noise-Sensitive Areas, defines the surface of a national park area (including parks, forests, primitive areas, wilderness areas, recreational areas, national seashores, national monuments, national lakeshores, and national wildlife refuge and range areas) as: the highest terrain within 2,000 feet laterally of the route of flight, or the upper‐most rim of a canyon or valley.