The Story So Far
My father-in-law grew up in New Jersey, ended up in the Air Force during Vietnam, and then met my mother-in-law while stationed in Missouri. His family basically disowned him for marrying a non-Catholic girl and he raised his kids in Iowa with little to no contact with any of his relatives.
Fast Forward to Present
My wife and I have a soon to be 3 year old. My FIL desparately wants us to go on a multi-week train trip to the East Coast to meet all his relatives.
There's plenty of issues here:
1) My wife doesn't get vacation time, if she goes, shes out 2 weeks pay.
2) My In-Laws are both retired due to disability. There's no way they can keep up with a 3 year old for 2 weeks on vacation. We never let them watch our son alone because they're not physically capable of keeping him safe.
3) Neither my wife or I have any interest in going since none of these relatives have shown any interest in us.
4) My In-Laws apparently hate each other and have as long as my wife can remember. They bicker and fight whenever they're together. Its bad enough that I've seen waitstaff duck behind potted plants to stay out of sight when they're yelling.
5) My wife has said "I love my parents, I just don't like my parents" We're just not interested in spending time with them.
No matter how many times we tell them this is a bad idea and that we don't want to go they won't drop the issue. They do their very best to guilt trip my wife and they're doing things like looking into ticket prices and booking hotels and other such insanity. They've worn down my wife enough that she's hoping they'll just die before the trip is to take place next august. She's not been able to convince them this isn't happening. My MIL is likely to throw a fit involving endless crying phone calls, emails, and appeals to everyone we know to try to talk my wife into it. It'll be messy.
So how to I get them to drop this nonsense?
FYI: We are in no way dependent on them for anything.