Trying to get them routine when it's our second child and your first is at nursery

My son is 3 and my daughter nearly 4 months. I was so regimented with my son when it came to feeds every 4 hours and naps at the same time each day. He went with it all like a dream and slept through from just 6 weeks and never looked back. How different could things be this time around! I feel like I have forgotten everything and I feel like getting a routine in place like before is so much harder. If my daughter is tired and needs her nap at 8.30am I have to get her in the car seat at 9am to take my son to nursery 3 days a week. The same when I go to pick him up! I hate it because I desperately want her to have scheduled naps for her own benefit for mine also! She is also hardly interested in her bottle sometimes only having 3ozs then going 5 or 6 hours before the next feed. I know she just isn't taking enough during the day to fill her up to sleep through and she doesn't. Albeit she only wakes, feeds and goes back off, the broken sleep is enough to make me feel exhausted. And unlike with my son, I am unable to nap when she naps as I have to look after my son. She will not take more than she wants to rake milk wise and as for dream feeding, my son would literally drain a bottle but again, she'll take a few ozs then she's done and will refuse to take anymore. I really thought I had this all down to a tea because my son was an angel to be fair but I just don't know what to do this time around. Any advice would be much appreciated. Thanks so much x