Originally Posted by
playfelt
With that wide an age span you would do well to separate your room so that the mouthers and crawlers are limited only to the toys it is safe to do that with. No one wants to reach into a bin of duplo and find a soggy mouthed toy. The babies will knock over towers, move the parked cars and disrupt the imaginative play of the older kids. It isn't their fault but that is just what babies do. And it isn't fair to the older kids to always have to make allowances. If the big kids have an area sectioned off where they are free to use the big kid toys that babies aren't allowed to go is another idea.
Open ended is fine but you also need to have some designing elements to inspire the play. Scarves are just scarves but if you add music they dance. Blocks are just blocks but if you ad a few people figures the blocks become boats and houses and barns for animals. Some playfood in the kitchen, bin of small stuffed animals that can double as story telling figures. An assortment of plastic containers or boxes that can be stacked or nested. Mine love the pile of empty yogurt tubs.