Simple question, are WAPs always configured from the default gateway's web interface? Do you ever have to go somewhere else?
are WAPs always configured from the default gateway's web interface?
Normally the "default gateway" (main router) has no relation to the WAPs. WAPs may have a management interface (console, web GUI, ...) of their own, or they're configured by their wireless controller.
Some routers integrate a wireless controller - then you'd configure the WAPs from that router.