> First - and this probably won't be popular - I'm not sure there any > horse out there except maybe Remington that can gait 100 miles and I > think he trotted a good bit
Remington uses mostly only trot. The tolt is a very demanding gait. It has a one foot push off which means one foot is pushing up all the weight at each stride. Not efficient for long miles. Icelandics are supposed to have good trots, unlike many gaited breeds.
