The trailhead is the Highline Trail trailhead/Hayden Pass off the Mirror Lake highway. This is at mile post 34.2, which is 34.2 miles from Kamas Utah on highway 150, or about 43 miles south of Evanston Wyoming on highway 150. The trail will likely be very snowy until late June in most years.

To Packard Junction (3 miles / 1.5 hours)
Follow the Highline trail. After 0.75 miles, a side trail comes in from Mirror Lake, stay left as the trail descends southeast along the base of the high Uintas.

Continuing on, a junction is reached with right going to Scudder Lake and left bypassing Scudder Lake. Either way is fine, but I recommend right to see the lake close up. Just after the lake, the trail re-joins the main trail.

Next up is Packard Lake junction, about 3 miles from the trailhead. Go right here.

To Packard Lake (1 mile / 30 minutes)
The trail heads south and passes near Wilder Lake before crossing a small ridge to Wyman Lake. Continue past Wyman, across one more small ridge, to visit Packard Lake. Of the 3 lakes, I think Packard is the most scenic, as it sits overlooking the Duchense River drainage.