My Daughters minnie is very spoiled like all of our animals here, she plays with her all the time has shown her some in Halter and does well with her. My daughter has talked about teaching her how to drive that should get interesting.
the size you are looking for is called a cob size. I would strongly suggest a leather harness. I have used nylon with disasterous results....I now only use them to train. The company I go through is called Center Square Harness Shop. Samuel Esh, he is located in PA. He will actually have you measure your horse at certain points and will custom the harness for you Good luck Deb
is thair a book are a web page that would help me with training my mare to pull i have never trained one to pull