naps for 2nd/3rd children

[waitingforsomething]

How do people ensure that their subsequent babies get enough day sleep? Or does it just have to be sacrificed a bit?
DS is always being woken from naps or having to have short snoozes on the go because we are forever taxi-Ing to pre-school/activities/friends house.
I'm pretty sure his night sleep isn't helped by this but is this common for others?

DD2 tends to do better if we are out and about, she struggles at home because DD1 is buzzing about and I think it distracts her. So I try and schedule the day so we walk to activities or leave a bit early and drive around for her first nap.

By 4pm it's usually all gone wrong and we end up with dd2 asleep on my lap and tv on for dd1!