This isn't quite "the early days of Sailor Moon"
per se, but I figured this was the best place to share this.
I turned up Toei's official English synopses for each season of Sailor Moon, plus the R Movie, from their old corporate website (copyright date 2009). Enjoy the Engrish!
Sailormoon:
All girls have a desire to be prettier, wiser and more sophisticated. The heroine of this animation is also one of such ordinary girls. And she makes her desire come true by becoming cute fighter, “Sailormoon”. One day on the way to the school, she helped a black cat bullied by children. The strange black cat who had a crescent patch on his forehead told her that she is a Sailormoon to protect the earth and the moon. The black cat gave her the magic brooch and told the key word to change to Sailrmoon. “Moon Prism Power…Make Up!” Then the light suddenly covered her and she turned to Sailormoon. The action and romance of Sailormoon now begin.
Sailormoon R:
Suddenly, a girl comes down from the sky. Her name is Chibiusa and her true character is unknown. Furthermore, her enemy “Black Moon” appears and tries to take away her life. What will Sailormoon do?
(Movie) Sailormoon R:
"Sailor" girls and Mamoru went to the plants garden. There appeared the boy named Fiore. He seemed to know Mamoru from long time ago. He disappeared soon but Mamoru did not recover his cheerfulness. Usagi also disappointed because she did not know Mamoru's past.
They caught the energy of the monster from the small planet passing near the earth. The strange flowers bloomed in the town and people suddenly attacked "Sailor" girls. People were manipulated by the flower. The girls changed to Sailor fighters and Tuxedo Mask also appeared. Tuxedo mask protected Sailormoon and injured. Fiore kidnapped him to the planet. Sailor girls transferred to the planet, and they fight against the flower monster. The monster Flower controlled Filore's mind. By the power of Silver Crystal, they destroyed the Monster and Fiore recovered his mind. And the town recovered the peace.
Sailormoon S:
New enemy, “Daimorn” attacks Sailormoon. When the overwhelming power of her enemy drove her into a crisis, two new Sailor fighters appeared. Are they her enemies too or are they going to be allies?
Sailormoon SuperS:
"Dead Moon" has come to catch Pegasus, who has only been seen in Chibiusa's dream. The Sailor fighters whose powers have elevated with the help of the Pegasus, are even stronger and more active in this series.
Sailormoon Sailorstars:
When a fearful enemy Sailor Galaxy appeared, three new Sailor fighters also came, in search of the princess of their planet. Now, the “Sailor battles” that will determine the fate of the universe is about to start.