VLF radio is very sensitive to noise, which is both interesting and terrible the same time. One example would be when I set up the VLF radio about 100 meters away from a railroad track and a train went past. Yes it's definitely noise, but it was pretty interesting lots of weird sounds coming out from around the VLF spectrum from the railroad!
60Hz noise is hard to avoid, so it's good to be far away from these noise sources and I do think a 60Hz filter could be a great addition to the circuit design.
The other factor with VLF radio is that there can be very large gaps between anything interesting happening which in itself is not so bad, it's just that this does not make for a great live music performance. It more something where you might go record sounds, then integrate them into your music later.