Lake Haiyaha can be reached from the Dream Lake area of Rocky Mountain National Park.  It can also be accessed from the Glacier Gorge - Mills Lake - Lochvale junction side, although the trail from that direction to Lake Haiyaha is not maintained.  Still a pretty hike, but is largely uphill.  Lake Haiyaha from the Dream Lake trail area - is uphill to Lake Haiyaha but mostly downhill to the Mills Lake junction.  It's pretty much all scenic in Rocky Mountain National Park.  These photos are from in front of Haiyaha - the lake itself it oftentimes rough unless you are there very early in the morning.