yep.... another nap Q

A&B September 17

We're having trouble with LOs evening routine.  She doesn't have a real schedule but everyday she needs to go down for a nap around 430-5pm (based off of trying not to let her get overtired, not being awake for longer than 2 hours and her sleepy signs).  H comes home from work around this time.  LO pretty much refuses to take her nap at this time... I'm guessing she knows he is coming home or if he is already home wants to stay up to see him.  We always try to get her to take this nap and can get her to sleep but not to stay asleep for longer than 5 min.  Because she skips this nap, she is then up for WAY too long and is a total mess.  We have moved up bedtime but it seems like we're going to be putting her to bed at 6pm pretty soon!  Any advice on what to do?  When are they old enough to stay up for 3-4 hour stretches?  TIA