This will give you an overview of Randolph. He was very influential in the Democratic party. Regarding his relations with Nixon, the President saw Randolph as a gentleman and an oldfashioned politician.
This is a speech by Pres. Carter on Randolph.http://www.presidency.ucsb.edu/ws/print.php?pid=30857
This article explains why Randolph thought moving the voting age to 18 was important during the Vietnam war.