How cold could it get?

My next Appalachian Trail section hike is from the James River Footbridge, to Manchester Center, VT in early June. Hoping to keep my weight down, my summer-weight equipment plan sports a 50 deg top-quilt, a 40 deg under-quilt, a lightweight merino base layer, a goretex rain jacket, light merino glove liners, a merino buff, and a windshirt.

Thought I better make sure that's gonna be sufficient. After all, it's still gonna be spring in the mountains...