Don't fret too much for a 15 mile ride.
Just bring some snacks and a water bottle for you and your horse. If they give you a halfway vet check or something (I don't think they will for such a short distance;) then pack a bag for the checks and maybe have a friend there or something.
I have no shod the horse I ride, nor does he have boots, but his feet are rock hard. If your horse is too tender, ask about the terrain. If you're crossing high rides and deep rock valleys, get some shoes. If not, then just go play.
Also, bring a camera! I was riding and snappin' pictures all over the place.
Pssh.I didn't pick up the wrong lead
It's called a counter canter...
...A very advanced maneuver.