Colorado law limits liability of equine accidents because of the inherent dangers. Every business that uses equines has this posted on their premises.
Sombrero Ranches rents a few thousand horses every year across northern CO. Some darn good, some so-so and some questionable. If you don't have experience with them or are not going to have someone along that does, it's best if you stay on foot.
More danger is involved driving that 1500 miles to the hunt area than there is on a horse.
Of course, I ride mules and that takes the stupidness out of the equation that many horses seem to have . A person does have to be smarter than the mule though.