A lot of them are made up, but many are based on actual locations. How could they not be, when I live in British Columbia?
We used to camp a lot up at Alice Lake, just outside Squamish, BC. One of our favourite hikes up there is the Four Lakes Trail, and many scenes in the Gatekeeper series take place along that trail, or at least they were inspired by those spots. For instance, the switchback path Phennil takes after his visit to the Tree of Life (Book Three: Gatekeeper’s Deception II — Deceived) is based on that trail, and the lake where Fredric gives Kyer the “secret message” (Book Two: Gatekeeper’s Deception I — Deceiver) is based on Fawn Lake.
The spot from which Kyer is taken by her enemy in Gatekeeper’s Key is loosely based on a section of Gold Creek along the Lower Falls trail at Golden Ears Park in Maple Ridge, BC. And the ride toward Ronav’s mountain headquarters is [again, loosely!] based on a drive we took in California years ago, where the mountain seemed to end abruptly and the plain began.
There are lots of others, too, mostly in BC. And of course Griffin and the Spurious Correlations takes place in Vancouver, BC, and Burnaby. No secret there!