You can access by air but I believe it is illegal to land aircraft anywhere other than a dedicated runway. Have to be dropped and get into a helicopter that is hovering but not touching the ground.
Most BLM is ok. USFS is at the District Ranger’s discretion. States make up their own rules. It’s best to check with the regional people at higher levels of management, not the LE or the public information folks. Or beg forgiveness.