Can a husband have sex with his wives in any room in his home, or is this permitted only in his wives' bedrooms? Is this allowed in a hotel? Where is it allowed to beggars?
There are general rulings on spousal intimacy: If you have intercourse with your wife you should be aware that some of your 'awrah might be visible, especially as the 'awrah of a woman is about the whole of her body. So as long as you can keep your 'awrahs safe from any foreign sight you may have intercourse at any location where foreign sight can be hindered by any means: be it by closing doors, windows or any kind of object. In other words you can't have sex at a location where you have no security from being seen and of course it is even sinful if you seek adventure and have sex in a location where there's a risk to been caught in the act!
Beside this there are prescribed timings where this intimacy can take place, and some kind of orders or dsiciplinary tactics which we are thought in the qur'an:
O you who have believed, let those whom your right hands possess and those who have not [yet] reached puberty among you ask permission of you [before entering] at three times: before the dawn prayer and when you put aside your clothing [for rest] at noon and after the night prayer. [These are] three times of privacy for you. There is no blame upon you nor upon them beyond these [periods], for they continually circulate among you - some of you, among others. Thus does Allah make clear to you the verses; and Allah is Knowing and Wise. (24:58)
The word "three times of privacy" is the translation of ثلاث عورات (literally three 'awrahs).