This Old Souse by Mary Daheim (2005, Paperback, Reprint)

Judith Flynn's cranky but loveable cousin, Renie, has always had a fascination with this older house in the neighborhood where she grew up. She convinces Judith that something strange is going on and they need to investigate. It doesn't take much to get Judith into a mystery! The house looks deserted but they find out that a couple, named Dick and Jane Bland, live there, but are rarely seen and they have all their food delivered. The cousins find that a mysterious package arrives at the house once a year. Being nosey gets you everywhere with the neighbors! Judith gets a surprise when a dead body shows up in the trunk of her car while she and Renie are doing surveillance work on the house. The police are pointing fingers at her as being the number one suspect. Judith's friends and family provide a humorous background, especially her cantankerous mother, Gertrude, who lives in a converted tool shed behind her B&B, her religious spouting housekeeper and her cat Sweetums, who is nothing like his name! On top of all this, Judith is trying to help her son Mike and her daughter-in-law, Kristen with their marital problems. I guess she hasn't heard that a mother/mother-in-law should butt out.
This book came out a few years ago and I always buy them right away. Some may not be as spectacularly funny as others, but I have grown to feel at home with the characters....like they were my own family and the even though the plot was weak on this one, just listening to Judith and Renie & Gertrude keeps a smile on my face!