I know with my ds once he is tired and in his stroller (or carseat for that matter
), well there isn't much to keep him from falling asleep. Thankfully I can transfer him (most times) to his crib without much difficulty... but that doesn't help you any!
If I sing or talk to him he will stay awake longer, but usually won't keep him awake for any long length of time
Sorry I couldn't be more helpful, good luck trying to keep babes up
Devon