ExDH has his own stash at his house. Although I think it contains some of 'MY' stash as some of my favourites have gone missing lol! DS tends to take toys from here as well. I pack a bag with his pyjamas and some nappies (although exDH buys his own though sometimes we split a pack) and the toy he wants to take with him that time. We are pretty fluid and let DS decide what comes home. It gives him a bit of control over the situation.
DS spends three weekends out of four with his dad.