Polly, yes in French trousers and so on are singular, but they are definitely not in Danish, Dutch and German which like English talks of a pair of anything that you insert your legs or hands into.
Hebrew, both ancient and modern, has singular, dualis and plural, and if I remember correctly Classical Greek does too, which is probably why we talk about a pair of glasses, (spectacles), gloves, shoes, trousers, pants etc.
To me staying at a place as opposed to staying in it, means you are on a visit, rather than living there permanently, but this is probably Scottish usage.