How Much of Britain Has Been Built On?
I wonder if you can help "sounding board" this?: I have a NaNo set in SoCal, where I wanted to have an ancient Weird Mystery Cave (the inside is a magic portal, don't worry about the inside). It would be good to stick it in a place where relatively few humans would frequent, but it still needs to be sorta same-day-drive-and-a-hike distance from LA/LA County, because logistics. Would the San Gabriel Mountains seem plausible to have an "isolated" cave somewhere in, or am I way off base?