YG When we moved house dss were 3 and 5, and at this stage a move to a playroom worked well for us. We use our second (huge) bedroom as spare room/playroom. We made sure we had good storage in the playroom for all their toys, and made them responsible for keeping it tidy. (Which mostly works well, though they do go through phases.)
We have 'craft' supplies in the breakfast room, but virtually all other 'playing' happens in the playroom (or the garden). They don't have toys in their bedroom, and rarely bring them downstairs. (Though we do play family games together in the lounge.)
We don't have TV or PC or anything like that in the playroom yet: they are still downstairs under adult supervision/limited access.
The boys share a bedroom, and ds1 plays or reads in the playroom in the evening when ds2 is in bed going to sleep.