How strong is the obligation to attend a close family member's wedding?

Well, I think you should consider sending your wife and your oldest kid.
You are welcoming a new member to your family. This is going to be your children’s Aunt.
And it nice to have your kids learn social skills at a family wedding.

Just some thoughts. You wife should go, overcoming most obstacles. If the kids can’t go, you need to stay with them. (unless there is someone who could watch your clan while your gone. Then enjoy a nice weekend with the wife.)

…do they still rent cars for “X” days and unlimited miles? (just putting a different idea out there)

Those “unlimited miles” deals from Enterprise don’t let you cross state lines.

Every time I’ve rented a car in the last few years I’ve assumed it was unlimited miles and I haven’t been called on it yet. Rented an SUV to take the family to Florida (from Virginia) two Christmases ago and that was unlimited miles.

Not that I recommend that for the OP. Send the wife alone.

Would you go if it were your sibling?

It is this writer’s opinion that you should go. I’d also posit that since you’re asking, you know you should probably go.

Believe me, I feel your pain. The bride to be of my brother-in-law decided she wants a winter wedding, and their wedding is on JANUARY THIRD in Iowa. You know, right after all the holidays that you spend all of your money on. My wife is in the wedding party, so she has to go to the rehearsals, and be indisposed with all the wedding party stuff the day of. In addition, we were also informed that our two year old son is the ring bearer. We also have a two month old son, whom we (well her, mostly) are breastfeeding, and that boy has an appetite. My sons combined form a Voltron of Chaos and Caterwauling. Further still, my wife’s family has a gift (holy crap) for overcomplicating the hell out of everything. So, yeah. I’ll be wrangling a toddler and and infant, managing toddler despair at the uniform and tasks he’s being given, trying to keep my wife together, all while the situation grows exponentially more untenable by the hour. I can’t wait.

It is safe to say that of all possible universes, the one I inhabit on January 3rd is the most shitty. The A Number One Last Thing On Earth I want to do is go to that wedding, and believe me I bitched and whined up a storm about it…but I will go, because it’s not about me.

I don’t mean to come across all hardass. I just know I am pretty gifted at coming up with validations and justifications for why I can’t do things I don’t want to do.

Most let you cross state lines. Some let you cross some state lines, but not others state lines. I don’t think any of them are happy if you go to Mexico, or that one spot on the north shore of Maui. (Not sure about Canada.)

I’ve never seen anything but unlimited miles. I did not have any issues when we drove to FL, and we put on over 3,500 miles. They didn’t bat an eye.

Well said.

If I’ve learned one thing in my life, it’s that family members close to the bride or groom far too often get really stupid about weddings, either about who is attending or who isn’t being invited. I suspect that MIL is very excited about the wedding, and maybe was hoping seeing the little Frylocks, and isn’t thinking rationally through the logistical issues. Ask her if she’d drive all that way for a short stay (no, don’t; she might say yes).

Anyway, I don’t think you have any obligation to go anywhere, anytime, as long as you and the Mrs. are in agreement about it. Send her off with a hug and a smile.

I read all the way to the bottom because I was curious to see if ANYBODY would agree with the MIL. :~)

Half way through through the OP, I was thinking, just send the wife…

By the way, talking of old customs, I was taught to never “refuse” a wedding invitation. Always “accept”, with the explanation that you won’t actually be present.

…“Thanks for the invite. We’d love to attend. Unfortunately, only I and my eldest will be able to be down there on that day. Husband will be staying here with the rest of the children”

My BIL got married to a gal from NJ, who only had a few family members in town. A vast majority of the guests were from Ohio, where she’d attended college. She chose to have the wedding in NJ. (At least it was in the summer so we didn’t have to take the kids out of school.)

That meant that all his brothers and sisters, aunt and uncles, his friends and her friends had to take a day off work and drive or fly to Philly. All of the siblings had young kids at the time, so it wasn’t an easy trip. We also had to pony up for three nights in hotel rooms, plus flower girl dresses/hairdressers/manicurists (yes, I know) for our daughters, tuxedoes and matching shoes for our husbands, and a babysitter for the reception.

What a PITA. But it was my husband’s brother and declining wasn’t an option. However, we all openly resented the hell out of his wife for putting us out like that. Had the wedding guests been split 50/50, it would have been understandable. But she had exactly 10 family members in NJ and her parent’s friends, all of whom were adults. It would have been far easier (and cheaper) for them to come to Ohio vs having us all drive to NJ.

But, we all made the trek because it was their brother. And if you’re invited to a sibling’s wedding, you move heaven and earth to get there. At least that’s the way it is in our families.

The only person who “SHOULD” go, if possible, is the wife. Her husband & the kids have no obligation whatsoever. It might be a nice extra to send one of the kids with the wife IF convenient.

If MIL is upset, MIL can pay everyone’s way.