Start from the small town of Bighorn Wyoming (south of Sheridan, signs on Interstate 90 will give exits to Bighorn). From Bighorn head south on SH 335 which will begin to head west and then becomes County Road 26, which is a good gravel road. The road climbs steeply up the eastern slopes of the mountains and not long after the grade levels out, there will be a sign for the Little Goose Campground. Leave the County Road at this point and turn left (south) onto Forest Road 314. This road is bad to the campground, 4 wheel drive recommended. To reach the Little Goose Trailhead, you must continue 4 miles past the campground which is a little over 2 miles from the beginning of the road. At the campground is a pretty serious stream crossing (high clearance a must). Even on my late summer trip, the stream was high enough that water poured in my doors, and my vehicle is higher than most. Anyway if you don't drive across, the Little Goose Trailhead is 4.5 miles up road 314. If you do cross, follow the road as far as you dare, it is extremely bad. I personally stopped about a mile and a half from the trailhead, because I knew I could walk faster than I was driving, and the potential for vehicle damage. is high. Several other forest roads branch off, but they are all labeled with numbers, just stay on 314. Once at the trailhead, things have just begun. The trail heads SSW, and is a consistant climb for 4.6 miles to the Solitude Trail Junction which is at the edge of treeline. The Little Goose Trail ends here and intersects the Solitude trail which runs NW one way and SE the other. Go SE (left). The trail drops down into a ridiculously deep bowl and then climbs back out on the other side. From the top of that saddle Highland Park (a very large alpine meadow) stretches out to the south. Follow the trail south until a faint trail branches off SW. This trail was not labeled when I went but is essential to saving time. It is called the Highland Lake Cutoff, and is shown on the Nat Geo Cloud Peak Wilderness map, though is not labeled. This faint trail wanders across meadow and marsh and then heads steeply down to Highland lake where it intersects the trail heading to Spear Lake. The end of the Little Goose Trail to the Intersection with the Spear Lake trail is about 3 miles. From the Junction head SW on the Spear Lake Trail for another 3 miles to Spear Lake. This is the base camp for Black Tooth Mtn.
From Spear Lake head almost due south to the easily visible waterfall just above the lake. scramble up the slope into the large basin. Several small lakes will be encountered, but at the second to last lake, the last one just visible ahead, head up the saddle to the west. It is the saddle north of Black Tooth, and south of what I think is called Starvation peak. Anyway, it is a bit of a scree trudge. At the top of the saddle it becomes more talus and boulder hopping. Head up the saddle to the obvious snow slope that heads straight up the mountain between the main and more westerly summit. Take the branch of the snow slope that angles the most to the right and follow it to the top. It terminates on the western edge of the western summit. From here route finding gets a little tricky, but the goal is to get on the south side of the ridge crest. For me it lead up and over a couple sloping, wet, mossy, and lichen covered ramps. Once on the main ridge, the ground on the south side is mostly 3rd class and dry. Follow the ridge east to the main summit and scramble up the northeast face by the easiest route. The difficulty of the climbing isn't an issue, but the quality of rock is. I don't think the route exceeds 5.2 or so, but the wet sloping ramps below the western summit and the black crumbly rock on the main summit make it feel somewhat treacherous.
The snow slope is low angle probably no more than 30 degrees at it's steepest, its up to you if you want to bring an ice axe all that way.