Neo-Western horse operetta; Murphy's Romance, by Max Schott. New York: Harper and Row. $8.95

Meet Murphy Jones. A retired storekeeper, in his mid-50s, Murphy likes horses, pretty women, and general sociability. A laconic talker, a stoic philosopher, and a widower, Murphy is hardly the sort you'd look to for romance.

So when Murphy falls in love -- well, the woman, divorced and 40 and having found one marriage enough, rejects him. Two years later, still friends, she introduces him to her aunt. Murphy marries the aunt.

Murphy's romance? A romance at one remove. For Toni, the 40-year-old niece, is, after all, getting on in years and needs settling down. Toni trains horses for a living, but to Murphy her future looks none too bright. She has a habit of going through men "like popcorn."

Murphy to the rescue. Murphy, now married, turns matchmaker, fixer, arranger , and in the role of kindly uncle, finds Toni a husband -- and that's the plot.

And where's the kicker?Is kindly uncle hiding a broken heart while marrying off the niece he loves? Is he an ironist, a Pagliacci, or worse still, is he bent on secret revenge? None of the above. Murphy is having the time of his life, fixing things. Far better than driving his pickup truck down California's back roads, roads numbered A to Z in one direction and 1 to 100 in the other.

The charm of this neo-Western horse operetta? Well, it hasm charm. the deadpan narrative lopes easily along in Murphy's nonstop telling of it. He has the dry wit of a desert fox and the shrewed observation of a small-town merchant. He judges men, horses, and towns by their quirky ways. We hear of a man who walked so straight and so even that "he used to measured out postholes to the inch just by walking." We hear of a loner who loves to chat: "A lot of these loners do. Once or twice a monthly they'll stop you and talk your head off. Gives them something to brood about afterwards."

Then there's desert town in Oregon, 4,500 feet up, where the winter "lasts from November through June and there's no spring at all, except some people like o call the first day of summer spring, when the grass jumps up about six inches."

Max Schott is a local colorist and a smooth storyteller. Maybe a little too smooth. This Western progresses with nary a bumpy road nor a pistol butt. Plenty of cattle, but no rushers. Schott's is neither the two-fisted old West of ernest Haycox nor the neurotic new California of Joan Didion. Schott's territory is 60 miles east of Los Angeles, where the badlands have been crisscrossed with asphalt and the horsy set is about as romantic as a feed bag full of oats.