If husband and family agree to take total care of the little fellows, fine but otherwise I am 100% with your DD. It would be no holiday for her with lack of facilities for starters. Let the more knowledgeable take over care but it has to be 24/7.

Are they upset for themselves?which would be a wee bit selfish(imo) or upset that your daughter has very sensibly decided not to put herself through unnecessary stress. perhaps a couple of days of visiting her & taking care of the little ones may be an idea ?

We took our oldest camping before she was two and before proper disposable nappies! Everything was fine except for the nappy problem.
We then went with both oldest DC when they were 5 and 3 but had another member of the family to help.

It depends how 'hands on' her DH is and if other members of the family will take turns watching the twins. Travel cots are a good idea as they have high sides and can be used as 'play pens' for safety if someone is cooking.

I don't think I would take sides Grammy6, let them decide for themselves.
'Whatever you decide, dear' is always a good policy.

I think it's a lovely idea for her DH and his family to take the twins for a camping holiday. She probably needs the rest at home by herself to catch up with herself . She could even do that Mumsnet thing of booking herself into a spa hotel.

We always camped as a family when my elder sons where small. I remember taking them when they were 6 months, 2 yrs and 4 years old. It is many moons ago, but I don't remember it ever being a problem and the boys loved it.

I think that your daughter needs to talk to her husband and outline who will do what while they are there so that she doesn't have all the work herself and she can actually enjoy the holiday.

What you and his family feel is neither here nor there - if your daughter doesn't want to go on such a holiday she's entitled to say so and her husband should respect that.

It's for your DD and her husband to decide if they go and who will do what if they do.

We have camped and caravaned since our girls were babies. They always loved it and it doesn't have to be hard work if everyone mucks in.

I think I would worry about them getting out the tent, lost in woods, falling in river etc. 2 year olds are quite fast on their feet. It may be easier for them to go to a lodge/log cabin?

I don't think you need to support her - just stand back and see what they decide - it is up to them and you would be wise to keep out of the discussions.

We have caravaned with very little ones and it went fine, but any holiday with 2 year old twins is going to be challenging!

Yuck! I can't imagine anything worse than camping as a holiday option.
Add twin toddlers into the mix and it's a no brainer.
If your DD feels under pressure from her DH and her in-laws, suggest that she makes it clear to them that she's not going to join them this year but she hopes they have a nice holiday.

It's up to her (and her DH) how they spend their family holidays and she needs to set clear boundaries now rather than cave in for a supposed quiet life, otherwise it will become an annual expectation/period of misery every year.

We went tenting with young ones and seen a lot of folks with even younger
If there is a family to look after them as well as the father and mother I wouldn't see a problem at all if she was doing it alone yes I agree too much but a mother father and inlaws shouldn't pose a problem but then at the end of the day if she really doesn't want to do it they will have to sort it out between themselves taking both points of view into consideration The other question is ...is he a hands on Dad and do the twins get on well with the in laws if he's likely to sit back drinking his beer with dad in law whilst she runs around after the babes then no

So tenting with small kids... yes if everyone shares the 'eyes in the back of the head' holiday. No if she's going to be on tenterhooks while they all relax

Yuck! I can't imagine anything worse than camping as a holiday option.
Well, I think for some people it is the only way to get a holiday as it is probably the least expensive option.

Even renting a caravan in August could be upwards of £850 for a week!
Are there caravans available to rent on the same site? Perhaps they could consider that as an option.

I can't imagine anything worse than a camping holiday with 2 year old twins, not a holiday for the mother at all.
One year DS and I took GC away and left their DM at home for a week, probably the best holiday she ever had

Is dd likely to be toilet training the boys? That would be a bit difficult in a tent. If she is concerned she could just say that she is planning to toilet train so will be happy to join them again next year

Not taking sides is great but if your DD is feeling a bit outnumbered by those wanting her to go camping, there'd be no harm in saying you see her point of view.

It doesn't matter how many people have wonderful camping holidays with toddlers, if you DD is primary carer for her two, and she doesn't want to go, that is entirely up to her.

Asking others to take over the care is probably not going to be practical, as she will just worry about all the unusual hazards in a camping situation and about the stand-in carers being unused to her twins' antics.

Your DD should stand her ground and not be pushed into a situation that will be too much for her.

It seems as if your daughter would stay home or go on her own holiday whilst her partner and inlaws camp with the twins? Why are her husband and his family upset? Because she can't cope and they will miss her?

I don't tell my grown daughters what to do, I listen to their moans and say 'there there'.

I read the problem that it is all the mums going camping with the children ?

You could try asking what exactly the problem is - and help her to break it down.
Is she %$off with her in-laws for making assumptions and not giving her choices?
Are there specific difficulties she has? I'm guessing she's not used to camping or she would take it in her stride.
Does she need to explain to her OH / in-laws and ask for help? Would they be unsympathetic, or does she feel that it makes her look bad?

Best for her relationship if she can talk seriously about the issue, rather than just enlisting her mum.

Had my DH not wanted to camp with me and our kids, I would have felt bereft. I'm wondering if that is how your SiL is feeling. Seems that the issue is acknowledging the feelings - and the different expectations.
It's also unclear as to whether this is their only chance of a holiday, or if there is enough money for your daughter to have a holiday or short break more to her liking.
I know not everyone enjoys camping - I have friends who don't.

Why is it too much for your DD to cope with?
Does no-one lend a hand, is her DH useless?

If so, there is more to the problem than the worry about camping.

Does dd simply not want to go, herself, but let the twins go with dh and his relatives? Are they upset because they'll miss her? Or because none of them want to take care of the boys?

Or does dd's staying home mean the twins will be, too? Are the others upset because they want the boys there?

Anyhow, I agree with those who say this is between dd and sil. His family needs to back away, but so do you. Maybe offer a few words of sympathy if she's feeling pressured, but that's it. Taking sides could come back to bite you. Please don't.

Is this a camping holiday in the UK , where it could be cold/ wet or somewhere like the South of France? could make a difference. Personally, I've found camping in France very relaxing and child friendly. If all the family were there she wouldn't have to do all the child care surely? The kids could run around and have a great time, but at the end of the day it's not your decision , its up to the parents.

To me the rub is the expectation that the inlaws appear to have that the young family will accompany them.

They are entitled to invite them to join them, and the young family is entitled to decline, for whatever reason. The grandparents are being unreasonable in showing their displeasure.

But your DD needs to decide her own reason for not wanting to go. If it's the expectation, then she should stand her ground.
But if she doesn't mind that, but feels it's too much work, she should just make clear that she would be happy to go as long as the twins' father and grandparents help with the childcare.

As far as the camping goes, a lot depends on the site's facilities and what sort of tent they have. My DD has just got a new one which is positively palatial and when they put it up in the back garden the other day I even heard myself say I would like to go camping with them later in the year

I would only camp in a tent when my children were small if we had a alarm on the tent door, my middle son would have been out of that tent in the blink of an eye during the night and off on an adventure ! I still had an alarm on the door the last time we went and said child was 13 but it was more for my peace of mind as DD who was 15 was in a tent on her own next to the main tent

The OP says "Last year was a challenge, but the twins were not walking yet".

So clearly her daughter knows what to expect in the way of problems and / or help. She has assessed this and decided she would not have a good time.

Why should anyone expect her to go, in that case?