Due to a promise I made with Shira, a case with a belt clip is out.
My assumption was that I'd have trade the fanny pack full of trail running gear, for a fanny pack with a phone in it. This is a bummer, because I actually do get use out of the emergency items I'd be swapping out, and getting a phone in and out of a little belt pack is much more awkward than pulling it off a belt clip.
Luckily, there's a solution out there. I give you the Running Buddy 6+ "Buddy Pouch":
The pouch consists of a pocket that comfortably holds the Galaxy Note 5 (with a case, no less!), and a flap. You shove the flap on the inside of your shorts, and thanks to a couple of high power magnets, the whole setup "clicks together" and sits firmly in place. It's amazing, I've got this huge phone attached to my shorts, and the Running Buddy doesn't jiggle one bit. It's truly impressive to see in action.
While it's a fashion disaster, I've found that I can run with my phone on the front of my shorts, and my trail running gear on the back. And while I won't win any style points, I am well prepared for whatever the road may throw at me.