we had a 3 bedroom townhouse. we used to have dd and ds1 in the same room and the older 3 shared with bunks and a single bed when they visited. its not often we have all 3 stepkids here at once (if we do its only for 1-2 nights). now we have dd in her own room with a spare bed and trundle for when the older kids stay (usually only dsd1 & 2 and often not at the same time) ds1 is on his own while ds2 is in the cot in our room. we will probably be putting ds2 into ds1's room soon and getting our room back but will wait until ds2 has started solids and is sleeping through the night more.
i find that its better for the kids to go to sleep if the rooms are just used for sleeping (1 or 2 toys/books is ok for first thing in the morning quiet time) and toys are kept elsewhere (currently in our loungeroom with some bigger items stored in the garage and rotated.)