Getting There: At the top of Thompson Pass trail #404 takes off just on the Montana side of the pass. There is a sign there where the trail takes off from the parking lot. The trail starts out very flat as you walk on the remnants of an old road and along the old canal. The canal used to bring water over from Montana to the mining activities on the Idaho side of the crest. It is about a mile of good walking and then you turn up the hill into a series of switchbacks. After a bit the trail lines out at a good grade for about 1.5 miles before you top out and drop down a grade for a bit before going uphill again; but not nearly at the same grade. 
Except for a rocky outcrop and overlook, the entire trail is under the forest canopy and well shaded. There isn’t any water along the entire route until just before the lower lake, so bring enough water for yourself and your dog.
To reach the upper lake cross over the outlet and head along the lower lake on a good trail; still trail #404. The upper lake is about a mile of easy walking in the shade, stay to the right on trail #537 at the half mile mark where the left fork (trail #404) continues to Pear Lake and eventually the state line trail.
At the Lake: I have found the fishing to be not as good as the lower lake. The fish in this lake look to be bigger but a bit finicky, at least to what I was presenting to them. Camping at the upper lake is posh for the backcountry. There is a camp there that includes a wood crafted table and several benches. There is enough room here for multiple parties or a large one. There was also a makeshift outhouse made of tarps just north of the campsite.
