My own experience suggests less of a binary division of the movement. Young people like John Lewis and Diane Nash with whom I, then 25, had the honor of working in 1961 were on the same page with older leaders like like Kelly Miller Smith and MLK. The intensity of events radicalized everyone and the only major difference seems to me to have been the decision regarding nonviolence or not.
Age had ramifications in terms of abilities and freedom of movement but it would be too simple to say that cutting edge was young and not-so-much was older. There was much more clearly a division between older people in the movement and their contemporaries. For example, in Nashville and elsewhere, churches of all sorts and racial makeups were largely passive and inactive.
My commitment to nonviolence was as much informed by Falstaff as MLK. Quite seriously, I regarded conflict, harm and violence as a silly way to solve things. I appreciate King more now because the religious basis of his body of thought seems to me apposite. Namely, he was a universalist and sat light to creeds. Nonviolence in the movement owed as much to folk like Jim Lawson, who conducted workshops among us, as to Dr. King.
Without students there would have been no movement. Students and a small group of older activists were the first freedom riders. The freedom rides started the ball rolling. Then there came more and more streams of participation. I tended at the time to see the early people as the beloved community and to venerate that reality even though it was sometimes ephemeral and unrelated to the ongoing times.
The CRM site is a wonderful trove of just the voices you are perhaps looking to make more prominent. Descriptions of particular local movements will indicate the degree of courage involved the more rural things became. I regard my involvement, though committed and still so, as a small drop in a wide river in which all aspects and permutations of "the movement" coalesce and move the world a bit closer to reasonability.