This is a wild shot to try to find the title of a SF story that has been bugging me.
I thought the title had 'galactic hero' in it, but that could be wrong, and it isn't Bill, The Galactic Hero by Harry Harrison. It was probably published in the 1960s or 70s, tho it could have been the 1950s or earlier.
What I remember is the hero is out alone (on our earth) in the countryside and it's raining. He sees what he thinks is a silo and gets inside to stay dry and then he falls asleep.
It turns out the silo is really a space ship. The space people (I think they're all humans) are on earth to hunt for earth game. They are nobles, and there is one female I think is a princess.
They discover the hero is there after they take off and assign him to be the cabin boy, cleaning, etc. They tell him to take care of the princess.
I think the princess is captured by space pirates and the rest of the book is the hero trying to rescue her. He takes various jobs on different planets and it turns out the skills he learns from those jobs help him rescue the princess.
All I want is the title and maybe the author so I can find it. I thought it might have been written by Jack Williamson, but I checked and it doesn't seem to be one of his books.