Sounds like you were on Lynn Camp Prong. At the trailhead, Lynn Camp Prong is on your left and Thunderhead Prong comes in from the right and joins it to form the Middle Prong of the Little River. The wide trail on the left is built on an old rail track left over from the logging operations of the early 20th century. The section that you fished above "The Cascades" is the section that is about to be closed for the next 3 to 5 years as it is returned to an all Brook trout stream.
BTW Congratulations on your good fortune and welcome to our addiction!