The NYTimes obit has this quote:
“In whatever guise — our own daily nightmares of war, intolerance, inhumanity; or the struggles of an Assistant Pig-Keeper against the Lord of Death — the problems are agonizingly familiar,” he said in his Newbery acceptance speech in 1969. “And an openness to compassion, love and mercy is as essential to us here and now as it is to any inhabitant of an imaginary kingdom.”
"A Visit with Lloyd Alexander" is at youtube in 3 parts here, here and here. It's a delight to see and hear him. In the videos he talks about his life, shows us his harp and some of his awards, sits at his writing table and shows us the room where he works, he talks about his writing process and much more. These videos really are a joy to watch.
SFSite has links to their reviews of his books. The Black Cauldron is a Disney film based on his Prydain books. Facebook has a group devoted to his memory and the ongoing appreciation of his work. NPR.org has a 2 1/2 minute audio obituary that was on All Things Considered.