I'm now reading a curious little book, a novel called The House on the Strand, by Daphne du Maurier. You may recognize the name because her work was twice filmed by Alfred Hitchcock, with Rebecca and The Birds. Strand depicts a businessman* who goes back in time and gets involved in political intrigue in Cornwall.
One thing worth mentioning is that the protagonist doesn't step foot inside a time machine. He takes a drug which an old school chum of his has developed. This book was written in the late sixties, and the idea of a time travel drug seems kind of native to the time. Philip K. Dick used it at least once, in Now Wait for Last Year.
The book isn't crazy psychedelic fantasy or Phildickian paranoia, though. du Maurier incorporates the premise into her own style, which is more staid.
* In a previous edit I stated that the protagonist was a scientist. In the course of the novel it becomes apparent that he isn't, although his friend is.