Bloom Peak is north of Kingston. Murray-Pritchard Area. It's right on the Idaho/Montana Border. As you're going east on I-90 somewhere around MP43, get off at Kingston Exit and head north.
Following the river, north, go about 21 miles north to a "Y" and stay left on the main traveled road. Go another 1.5 mile and stay straight. If you where to go right, that would take you up to Thompson Pass. Go about another 6 miles to an intersection with a road to your right. In the mid-winter you can unload here. From there it is more than 10 miles on the trail (about 1/2 that if you climb the power lines) to the base of the ridge. for bloom peak, find Pritchard, Idaho on the map and than look towards the montana border. Pritchard is up the cda river. You may want to plan on bringing extra gas.
There is an alternative trail ride; back about a mile from the (above) unloading area, there's a small, subtle trail on the right side of the road, as you are going north. There's not much room to leave your truck and trailer at that point. You could unload up the road and ride back down here.