Narrowboat Summer by Anne Youngson

 Ironically, I was reading Narrowboat Summer and my book group book, The Little Paris Book Shop, at the same time--and both are about a disparate group of people who find themselves on a boat together sailing down rivers/canals. One is set in England, the other in France. 

In Narrowboat, Eve (who just got fired from her engineering job for telling the truth) and Sally (who just left her perfectly nice husband) meet by accident as they're both walking along a path near some narrowboats and hear a dog howling as if in pain. They decide to see if the dog needs help and he escapes. They wait for the owner of the boat (Anastasia) to come along so they can apologize for losing her dog. Anyway, the 3 women bond and eventually come up with a plan. Anastasia needs some medical tests done so she will stay in Eve's apartment while Eve and Sally (after some intensive instruction) drive her boat down the canals to Owen's shop for repairs.  The book is about their adventures on their respective journeys.

Not sure in real life Eve would let a total stranger stay in her apartment or that Anastasia would entrust her home on the water to 2 inexperienced strangers. But if you accept that premise, it's a gentle, pleasant story about finding out what matters most to you in life.