A quick note on horses.
I grew up in a farming family (beef and wheat on dad's side & quarterhorses on mom's side) and have been a rider for longer than some of you have probably been alive.
Horse speed should be about 3, with high athletic score. Galloping (fastest gait for a horse) can hit as high as speed 5, but only for an exceptional horse and only for a very
short time. Typical gallop would be speed 4, but if sustained for very long it will kill the horse - exercise-induced pulmonary hemmorhage is an ugly thing.
Speed 3, a canter can be maintained for long distances, but typical riding would be a walk or trot which would be speed 2-ish (up to about 10 mph).
Horses are surprisingly fragile for something as big and powerful as they are - particularly their legs, knees & ankles. They require a fair amount of attention and a hell of a lot of food and water (been on the other end of that pitchfork a time or two).
Just some info for rp purposes - dramatically, of course, horses are seldom bound by real horse abilities (unless it's important to the plot.)
(My great-grandfather bred registered quarterhorses. My great-grandmother raised Shetland ponies and registered pekingese. Their farm was like paradise when I was little. "After you're done riding the ponies, you can go play with the puppies until dinner."