Think KB has covered most of the corners but also you need to tell us more and read a bit more, become aware of your options.
To give examples:
Are you able to hook up to electrics and is there a water pump or do you need to hook to water too? I have recently sold our campervan and want to ensure it's the same sort of "mod cons" for our family of 4.
Electrics. What the Dandy came with originally is a bit mixed. some will have nothing. So it's using a commando extension that easily slips into the Dandy. Some will be wired for mains originally, many will have been wired for mains by former owners.A few will have mains and a leisure battery.
Water pump yes. "Do you need to hook up to water too?" Hook up to water? I'm wondering what level of campsite or campnig experience you're used to. Anything more advanced than an Aquaroll is beyond my experience.
You sold your campervan and want the same level of luxury for a family of 4. Well what is a campervan? Anything from a Ford Escort (I'm old) Citroen Visa sized conversion to, if you have a pre 97 licence a 7.5 tonne behemoth. It might or might not include fridge, freezer, heating, hot water, toilet and shower.
What is a family of 4? Now it's not like me to be PC but even I recognise that not all families include a Mum and a Dad also kids ages vary. So Mum, Dad, son 14 and daughter 12 is very different to Mum daughter 8 and twin boys 4.
Security, towing and servicing. It's the standard folding trailer or caravan options. Hence me saying you need to read. Towing the largest and most luxurious dandy can legally be towed by a hatchback with the ability to tow 1 tonne. I think peridot managed this. would I do this NO. We've had some reports of instability with the late model (only the late model) Destinys. Servicing, minimal most important thing is to buy well.
It's not my intention to give you short shrift. i could write pages in response but that is a waste of my time if this is a very preliminary enquiry. Come back with more detail and I'll give more detail too.
Best of luck with your search.