Does this show that I'm old, or just that I'm crotchety?
OP said she was carrying an M&P, and my mind immediately saw a 38 revolver.
I wondered why she was riding down the road. It seemed like it would make more sense - for the sake of the horses' feet and the wear of the horseshoes - to ride along the shoulder. In the grass and the dirt.
That dog should enjoy walking along the blacktop in a month or two, during high summer.