It was set in the (US) wild west, but had a foreboding house. There was a cowboy and I'm pretty sure there was an alien. I don't remember why I keep thinking it was written like a gothic romance novel.
I'd like to read it again, simply because it was so 'odd'.
It might be The Hawkline Monster: A Gothic Western (1974) by Richard Brautigan. That is a critically acclaimed science fiction, western, gothic, romance novel that was published in the mid-seventies. The story takes place around 1900. Two gunmen are hired to do a job at a creepy, isolated house on the western plains. My paperback has a great painting of the house on the cover. The gunmen were hired by twin sisters to kill a monster that lives in the ice caves beneath their house. Their father, a scientist who was conducting experiments in his basement laboratory, disappeared and they believe he was killed by the Hawkline monster. The novel reads like a product of the sixties -- surreal and drug-trippy in tone. 'Odd' describes it well. Brautigan was a celebrated counter-culture writer and this was his only foray into science fiction. His most famous novel is the even more odd Trout Fishing in America (1967).
