Ruby Mountains near Elko, Great Basin National Park near Ely, Lake Tahoe, Berlin-Ichthyosauer State Park are all good options in Northern Nevada. You won't find the scorching hot temps of Southern Nevada either.
Don't know how adventurous you want to get but Northern Nevada has plenty of hidden gems.
Southern Nevada has some ghost towns and easy access to Death Valley but the temps down there in summer are scorching. I would concentrate on Northern Nevada if you would like more tolerable summer weather.