The New York Times has more details in an interview with Brian and Mike Love:
Q. I’m very curious about the new album. How is that going?
Mike Love: It’s going really well. Brian has worked on some great tracks, great melodies, great harmonies, and he’s been dealing it out to all of us. It’s really sounding good.
Q. Are the songs written and just waiting to be arranged and recorded?
Wilson: Most of them have been written. We’re going to have to write a few new ones, but most of them have been written. On the album, one song flows into another and that flows into another like that, until it’s over, until there’s no more album.
Q. So it’s something like “Pet Sounds” and “Smile.”
Love: There’s a little bit of a suite that’s meant to end the album, so it’s going to have a nice little touch that way.