As I reread Gilman's Herland, I couldn't help but think a bit of Angel Island, by Inez Haynes Gilmore: another sci fi/fantasy/utopia novel, where explorers happen upon a coven of undiscovered women and hijinks ensue. Although both get a bit preachy at times, it's fascinating to get a glimpse of how people a hundred years ago imagined gender equality. Brings me back to the good old days of college (I double majored in journalism and gender studies). And Gilman's words still resonate:
"It is not that women are really smaller-minded, weaker-minded, more timid and vacillating," she said, "but that whosoever, man or woman, lives always in a small, dark place, is always guarded, protected, directed and restrained, will become inevitably narrowed and weakened by it."
Although not of the same genre, if you're in the mood for a light read and you like literature of the early 20th century, I'd recommend Gilmore's first book, Maida's Little Shop, a charming children's book that spawned a long-running series about the girl and her friends. The first one, at least, is available for free download via Project Gutenberg.