We stayed overnight at a guest house next to the main ger camp at the entrance to the park (which was fully booked when we went in mid-October; other camps were closed for the season). Our guide said that maybe it was because it was October (she had only been during the summer), but we saw more horses from the road through the park than she had ever seen. It was amazing. At one point, we were standing in a field completely surrounded by horses, who were obviously used to seeing people. We also saw dozens of red deer. It was the beginning of their mating season, so the males were trumpeting and chasing each other off. One of the most incredible wildlife viewing experiences I've ever had. I recommend staying overnight, because you will see more wildlife in the early morning and evening hours. We were there in late afternoon/evening when we saw the most horses. We also could hear the wolves at night, though we didn't see any.

This is a rugged park, with rough "roads" of dirt gulleys, so make SURE you have four-wheel drive and high clearance on your rig.
These horses are the last truly wild horses in the world, reintroduced after extinction in the wild from breeding stock in Canada. They are as tough as their range, and stir the heart. The wild deer in this park look like American Elk, with huge antler racks

It is good to hear the wild horses story and happy that the horses are back in nature. The national park authorities do a good job. There are not only wild horses but also many deer and gazelles. The place is only 2 hours drive from Ulaanbaatar capital and the ger camp works in winter.