How about Peter Rowan? He sometimes goes to excesses, but his later work is exceptional. If you want to hear bluegrass songs with intelligent lyrics, yet with a handle on the traditions of bluegrass, atry his CD "Bluegrass Boy". It's hard to find a song to match "Let the Fields Go To Seed", his tribute to Monroe. Actually, there might be as good a song in "Walls of Time", one he co-wrote with Monroe. He tells of a night on the sie of the road when the bus had broken down and he and Monroe were walking and Bill gave his songwriting advice to Peter; "You hear that? You have to be able to hear that. Those are the 'ancient tones'."