Judith Cranswick, Fiona Mason is the right person for the job.
After the death of her husband, Fiona decides it's time she found a job. (A note: Authors of books featuring women in her 50s, please don't make them out to be simpletons who have never held a job. This is the 21st century, not 1960 and I would venture it is rare these days to find a women who has never had a job.) Off my soapbox.
Fiona's job at Super Sun Executive Travel as a tour guide on a bus trip to the Netherlands starts off with a missing passenger who turns up dead near their departure point. The authorities believe he died of a heart attack and send Fiona and the bus inhabitants on their way.
There's the usual cast of complaining tourists on board and Fiona has her work cut out for her
keeping the rowdy crowd entertained. After a brief tour of Rotterdam, the bus makes its first stop in the famous Keukenhof Park, the world's largest flower garden. When another guest fails to return to the bus after the garden visit, his wife and another couple wait at the garden while Fiona takes the rest of the group back to their hotel. More trouble ensues and a mysterious man from the government appears on the scene.
On one hand I enjoyed the tour of the Netherlands as seen through the eyes of Fiona and her tourists, but the switching back and forth to three narrators somehow was disconcerting. In addition, one line very early in the book tipped me to the killer. I think without that one line, the mystery would have been more difficult to solve.