This album was part of my shopping spree for Ohnuki tunes over my final year in Japan. According to Shinichi Ogawa's（小川真一） writeup for "Sunshower" in "Japanese City Pop", Ohnuki was still developing as an artist on this album. I can agree to a certain extent. She makes some dips into genres such as fusion with "Furiko no Yagi"（振り子の山羊） "Swinging Goats", Latin with "Kusuri wo Takusan"（くすりをたくさん） "Lots of Drugs", and though I can't remember which track exactly, one of the later songs even has some techno...hinting at where she and fellow contributors to the album, Haruomi Hosono（細野 晴臣）and Ryuichi Sakamoto（坂本龍一） (of YMO fame) would be heading musically within a few years. It's interesting to see all 3 photographed in the album booklet back in the day, looking distinctly hippieish.
The above link is for "Tokai", （都会）"The City"which, according to J-Wiki's entry on the album, was influenced by Stevie Wonder. In the song, she talks about the unhealthy obsession with urban life and proceeds to leave it. The aforementioned "Kusuri wo Takusan" also gives the message of a cheerful indictment on how the medical industry was, even at that time, overmedicating its patients.
This link is of the first track, "Summer Connection". The J-Wiki comment only mentions that it was written with a summery image in mind. My observations is that it's the only song that I can remember of hers in which she REALLY hits the high notes. Ryuichi Sakamoto's arrangement is such that it has that nostalgic "Summer of '77" feel to it.
March 7 2017: I've just made a follow-up article on the album.
October 31 2017: You can take a look at a wonderful cover for "Tokai".