Somewhere quite and private - give her a box big enough to fully streach out - but not too big as the kittens could get seperated from mummy and get cold - have a nice soft blanket in the box for her - its very important the kittens dont get too cold - I would recomend a covered heat pad to help them dry out after being born - the blanket will get very wet during the birth, but be carefull about changing it as some mummys dont like it to be changed.
WE only ever had one female cat that had kittens many years ago. We had a nice cozy box prepared and Simba was delighted with it, spending most of the last few days there. She gave birth at night when we were asleep and she had them in the coalbox of all places. I imagine having babies on top of lumpy coals is not very comfortable. We shifted them to the box and she readily accepted and nursed them in the box no problems.
I must say, we've always had crazy animals though.
It's important to offer her something warm and comfortable (introduce her to it beforehand so that she knows it's her place if she wants it), but she may well insist on using some other place and if she does, you just have to go with it rather than risk upsetting her. They like somewhere out of the way, quiet and safe. I hope everything goes OK. How long to go?
The wardrobe seems to be the best choice, I left boxes all over the house made up with lovely soft blankets etc. our cat gave birth in my sons bedroom cupboard, probably because he never used it, he hung clothes up on the floor! lol.