Floor bed sleepers - what to do when away from home?

[Creatureofthenight]

My DD (18m) sleeps on a mattress on the floor of her room. We are staying with a relative this NYE and I’m not sure what to do about where she sleeps. Me and DH will have a double bed but it will be very squashed if she’s in with us. I think I’ve read v young children shouldn’t have blow up mattresses? So can anyone advise me on what you’ve done when away from home?

What about something like a Camping mat ?
Can pick up very cheaply at any outdoor store and roll up small and easy to store.

Or a yoga mat ?

Did she have a cot, and could you take the mattress from that (assuming you're travelling by car)?

She sleeps on her cot mattress but there isn’t room in the car for it.
Good idea @BackforGood, we actually have a couple of these but had forgotten about them! Will give them a try.