To think I can squeeze into a 5 person car with just 2 other people

This is appalling behaviour from FAMILY.
You are the 'mum' here going to see your son off (is he in the Navy?)

Is there any chance that one of them could go by train?

I'm wondering how old your dad is and if he's able to take a train, or your sister?

Or- they can surely travel lighter and fit you in.

Failing all of that- have you looked into a coach?

My car is bigger than a Puma, & the back seats have to fold down to fit in the luggage for 2 of us.

It’s all a bit weird. I don’t think your DS respects you or values you.

They do however, respect your son.

Have you got a track record for cadging lifts and ducking out of driving?

Adding another person changes many things. With your pain, are you really going to be happy sitting in the back seat? Will the front seat passengers need to move their seats forward to give you more space? As someone with long legs I typically have mine all the way back. You will have your own preferences for temperature and air. There are additional people to consider for breaks and agreeing on a place to stop to eat.

traveling is already incredibly stressful and difficult. At least travel is difficult for me as I get travel sickness and have other issues. I think through every detail to try to make it as smooth as possible. Adding an additional person isn’t just about having a seat in the car.

That seems like a lot of stuff and quite specific to your outdoor hobbies , the father and sister here are going to stay in a nice cottage after seeing of their grandson/nephew, so will presumably mainly need clothing and toiletries maybe food but you could always do a click and collect near the property which is better for fresh things anyway.
I'm assuming that's why you have the note , because it's flexible for that kind of equipment, I had one as a work hire car once. They probably are a similar size/capacity to a puma

When you say Ford Puma, do you mean one of the newer model SUV type, or the 1990s coupé? Because if it's the latter you really wouldn't want to travel very far squished in the back so they're doing you a favour refusing tbh!

My SIL does this sort of thing with PILs. Both her siblings are married and have DC, she is neither married nor a parent. She doesn’t live with her parents, but she openly says they are the only family she has so they should prioritize her over her siblings. She gatekeeps her parents, I guess. And they let her do it because her siblings allow her to and pity that she has to do this sort of thing. It applies to all sorts of things: who gets which room at Christmas (she will get the master as a single woman, her siblings + kids have to sleep on air mattresses and bunk beds in a single smaller room); she will get ££££ tech and jewelry for her birthday, her siblings will get a card; her dad does all her diy (changing lightbulbs, putting air in her tyres, changing her air purifier filter - she lives 45mins away from them) often timed for weekends when she knows her nieces /nephews will be staying with them. It’s exhausting and pitiful, but what can you do 🤷‍♀️

Wow, this is really mean.
Can you offer your sister the cost of what your train fare would be, to offset the fuel costs (though I would imagine she would be in profit, knowing how expensive rail travel is in this country!).

I hope she sees sense @Emma6cat .

And if I was your Dad I’d be tellling her to take you instead of me!

How unkind neither of them will help you out.

Don’t want to get involved shows he’s weak in their relationship. Probably because she lives at home and he’s going to be relying on her.

Frankly your sister is being a cow.

If I was your son I’d be telling her not to expect to meet if she couldn’t at least try and make his mums life easier. I’m sure you are emotional enough about him leaving for a year without your sister trying to control the whole meet up.

Frankly your sister is being a cow.

If I was your son I’d be telling her not to expect to meet if she couldn’t at least try and make his mums life easier. I’m sure you are emotional enough about him leaving for a year without your sister trying to control the whole meet up.

Don’t be stupid. We don’t have the whole story so no the replies are not ridiculous at all. Maybe the sister is nasty but equally there may be a reasonable explanation why they can’t take op. We only have one side of the story. I hate it when people who grow up in a Walton’s style family think everyone else does too or believe family should trump every thing else. Not for everyone it doesn’t. I’m sorry for op but she needs to speak with her sister and dad to see if there is something else going on.

That sounds very selfish. I can't understand that at all

Is your ds in the navy?

I think your sister is being horrible. Can your son come to meet you half way?

The current Puma is a Fiesta on stilts surely, not an SUV, and sits at the bottom of Ford’s range. It’s definitely not big - Avis in Nice have them quite often so I have driven a few. But there’s plenty of room for 3 people, as long as they are not all six foot four. There is something other than the size of car at play here…

I think there might be some confusion over the Ford Puma bit. There is a fairly small older Puma, which might be tight for three adults and all the luggage (but not impossible). The new Puma is a decent sized SUV, and if the dad and sister are travelling in one of those, they are being very unreasonable in not giving the OP a lift even just one way.

If its tricky by train, OP, would you be able to go by coach?

Its a don't want to, not a can't.

Your sister just doesn't want to spend time with you. Not to drive you and not to share accommodation. It could be sorted so easily and most families woild do it automatically, she just doesnt want to.

Even if space was a problem, you don't make someone take 3 trains if they're going to the aame destination. You figure it out. You don't just say no.

That sounds very mean. Its your son after all.
What luggage are you and they taking? We go as a family of four for a weeks self catering in a normal car with all our luggage.

So what did you sister say when you asked her how you wouldn't fit in the car?

As to the pps saying that of course your sister couldn't fit you in the car - it's a one week trip, how much stuff do they need to bring?

We used to go to a campsite in France for 2 weeks when we were kids - 2 adults, 2 or 3 kids, bags with clothes, beach towels, toys, teabags etc etc and we fit in a regular car.

So your son is going away for a year and you, your DSis and DDad want to travel down to see him off. They decided to stay for a week but you can only stay for 3 days. They have booked an apartment while you are in a travelodge. I think this makes sense rather than paying for a larger apartment for whole week. You were planning to drive yourself there and back but now can't and want them to drive you there, but take the train back. It does seem odd that they won't accommodate this. But they may well think if you can manage the train one way why you can't do both. I imagine all the reasons will be linked to backstory and state of your relationships with one another rather than anything posters can provide an explanation for.

YANBU!
I could never do that to family. They would fit in one way or another. How much stuff can two people possibly need for a week in an apartment?

Your sister is a cow and your Dad is useless. I don't usually go in for tit for tat, but I think it's reasonable here.

You definately need to spend some time with just your son, if he's free he can meet you from the train, have some meals out just you and him. You don't have to play nice with your sister and 'share' the moment with her.